# Hot Math Posts

### How To: Identify the slope and Y-intercept given y=mx+b

This tutorial shows how to identify the slope and y-intercept given the formula y=mx+b. In this formula m is always going to be the slope and b is always going to be the y-intercept. Therefore if your given a problem like the one displayed in this video: y= 8/3x + 9, the slope would be 8/3 and the y-intercept would be 9. When given these problems all you have to do is match the given numbers to the formula to find the slope and y-intercept.

### How To: Solve polynomial word problems in basic algebra

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to solve word problems containing polynomials.

### How To: Find intercepts on a calculator TI-83

NotesCollegeAlgebra teaches you how to find intercepts on a calculator TI-83. You start with y plus 1.7 equals .8 times x squared plus 1.4 times x. First you subtract 1.7 from both sides, you get y alone on one side. The window should be set to -5...5, -5...5. X scale should be at 1, y scale at 1 and x rez at 1. Make a graph for it, like a parabola. Use trace to get y intercept at negative 1.7. The x intercept is about .85. Continue to use the calculator to get all the values that you need.

### How To: Calculate sales tax in algebra

In this math lesson we will learn how to solve math problems involving sales tax. Remember these two important formulas:

### How To: Find points on y-axis a certain distance from a point

This is video on mathematics. It specifically deals with geometry. The video describes how to determine where the y-intersects are when a point and distance to the y-intersect are given. The author starts out by giving an example ordered pair. The speaker next shows an example of how to solve such a problem. The speaker uses the distance formula along with the given distance and x-coordinate in order to solve for the y-intersect values in question. Most of the video entails solving this example.

### How To: Do a rotation in Geometry

Learn how to do a rotation in geometry with this video! First step is to pout the pencil into the compass. Adjusting the pencil and compass needle is same. Suppose you want 165 degree size circle. Measure the reading with compass in protractor. Note the point and adjust the compass. After place the sharp end of the compass at the point and rotate the compass the circle will enabled. Next use protractor. We see 75 degree acute angle. Place the protractor on the line and mark the reading we wan...

### How To: Graph square root functions & inequalities

On Yay Math, Robert Ahdoot, founder of Yay Math, will show you some square root functions and some inequalities. He begins with the problem y=x². Then he makes a sketch with two intersecting lines in a t shape. The problem is illustrated by a curved U shape, the U's bottom resting on the horizontal bar, which represents x, while the center takes the vertical line. The vertical bar represents y. This U is directed up because the x² is a positive number. If the number were negative, the U would...

### How To: Reduce a fraction to its simplest form in basic math

Fractions are numbers of the form a/b, where a and b are integers. Fractions are also called as ratios. Fractions are further divided into proper fractions and improper fractions. Proper fractions are those where the numerator is less than the denominator and improper fractions are those where the numerator is greater than the denominator. As fractions are ratios a fraction can have many equivalent forms. Multiplying the numerator and denominator of a fraction with a same number gives a fract...

### How To: Find the inverse of a function in algebra

Need a little help figuring out how to find the inverse of a function in algebra? Watch this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this free math tutorial, you'll learn how to calculate the inverse of a given algebraic fun...

### How To: Solve simple interest algebra problems

In this math lesson we will learn how to solve problems involving simple interest. When you deposit money in a savings account, the bank pays you interest at a certain rate called interest rate. There are two types of interest: simple interest and compound interest. In this lesson we will talk about simple interest. We will use the following important formula:

### How To: Solve a word problem for the perimeter of a rectangle

Need a little bit of help figuring out how to solve word problems involving the perimeter of a rectangle? See how it's done with this free video math lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Find the domain of a function in precalculus

Looking for a primer on how to find the domain of a function in precalculus? Learn how with this free video precalc lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Multiply two or more fractions and simplify your answer

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to multiply and simplify two or more fractions in prealgebra.

### How To: Match quadratic functions

This is the demo showing how match quadratic equations in the graphs. Plug in x=0. So everything with x cannot disappear. There is only one negative three in the equations. Let's look at the equations that has the four as y in the set. One of the difference between each equations are the negative in front of the x square and not in the second one. B is the set which opens down and C is the set which opens. Now lets look zero as y on each set. Both of them are opened. Let's look at X intercepts.

### How To: Find the area of a rectangle

The area of a rectangle is the basis for all geometry. You will need to know how to do this in order to better understand other objects. This video tutorial will show you the formula for area of a rectangle and how to use it. Don't be confused in math class anymore.

### How To: Clear decimals from a linear equation

Need instructions on how to remove decimal values from a linear equation in algebra? Learn how with this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Find the number given its percent

This video will provide you with insight into how to find a number given its percent. In the example provided, you needed to find the number which 33 is 60% of. This was achieved by simply taking the number which is a percentage of another number, in this case 33, and divide it by the percentage, in this case 60%, or 0.6. By carrying out the long division from this step, you will be able to find the original number and solve this seemingly complicated problem with ease.

### How To: Factor trinomials by trial and error in algebra

Looking for a guide on how to factor trinomials the brute force way? See how it's done with this free video algebra lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Find the equation of a line in point-slope form

When you are given a point through which a line passes and the slope of that line, you can calculate the equation of that line. The general equation to solve this kind of equations is called as point-slope form. The point slope of a line passing through (a, b) with slope of m is (y - b) = m * (x - a). Now substituting the values in the above equation you can obtain the equation of the line in terms of x and y. In case you are given with two points first find the slope of the line which is the...

### How To: Find the sum of reciprocals of complex numbers

In this tutorial the instructor shows how to calculate the sum of reciprocals of complex numbers. If you have to find out the sum of the reciprocals of two complex numbers first you will have to find out the least common multiple of the denominators. To do this multiply the numerator and denominator of the first fraction by the second complex number. Similarly multiply the numerator and denominator of the second fraction by the first complex number. Now you will have two fractions whose denom...

### How To: Convert between customary units of measurement

In this video tutorial the author shows how to convert between customary units. He gives a chart which contain various convention tables showing the equivalents of various measurement units. He says a general rule that when converting a smaller unit to large unit we divide the numbers and when converting a larger unit to smaller unit we multiply the numbers. He takes a few examples and shows how to convert between various units like feet, yards, inches etc. This video shows how to convert bet...

### News: Encrypting Passwords With an Old-School Tabula Recta

Have an old-school tabula recta lying around? No? Then just print out the chart below. Nothing ensures better password security than this centuries-old cipher technique. Here's how it works, via Wikipedia:

### How To: Solve negative exponent problems in basic math

Looking for a guide on how to work with negative exponents in basic math? From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to solve simpl...

### How To: Use the percentile formula in Statistics

In this tutorial the instructor explains the percentile formula. He says that the percentile formula is used to find the percentile rank of a data point in a group of data. He takes an example that consists of the lengths of puppies. Now he intends to find out the percentile rank of any puppy in the group. He shows that the formulate to compute a percentile rank of a particular puppy is rank R = 100 * (N< + (1/2)N= )/ Nt, where N< is the number of puppies whose length is less that the length ...

### How To: Graph the absolute value of a function

This video shows the method to plot the graph of the absolute value of a function. The video shows the example of the function of cube root of 'x'. The demonstrator first plots the graph of a cube root function. This is done by taking the reference point of positive one and positive eight. The graph is drawn for both negative and positive values of 'x'. After this the graph of absolute function is drawn by taking the absolute value of the cube root function. The resultant graph comes out to b...

### How To: Solve an equation using the point slope form

In this video the instructor shows how to derive a general equation for a line in Point-Slope form. The slope of an equation is the ratio of difference of y coordinates to the difference of x coordinates. In other words, slope is the change of y up on change of x. So you have the basic slope equation m = (y2 - y1)/(x2 - x1). When you have fractions you can simplify them by multiplying the denominator to the numerator on both sides. So multiply the equation by (x2-x1) on both sides. This gives...

### How To: Solve a number sequence

Check out this instructional math video that demonstrates how to solve a number sequence. These are basically a list of numbers, and there's a pattern to figuring out which number will come next. In the 15th lesson, learn how to solve SAT problems using the Official SAT Study Guide. Here are the math problems and their page numbers that this video covers:

### How To: Understand basic probability with examples

This is a very basic overview of probability, possibly intended for an eleven year old. It is a very good introduction to probability for one that has never encountered probability before. The instructor is not always clear in his intentions. Someone watching this video would learn about probability, ratios, percentages, and fraction. There is a set of required knowledge to understand what the instructor is talking about. The instructor uses very nice diagrams and also gives nice explanations...

### How To: Multiply two fractions

Fractions can look scary. But, don't worry, their bark is not as big as their bite! In this tutorial, learn how to multiply two fractions and simplify the answer into the smallest possible outcome. The basic process is to multiply straight across. Multiply the numerator times the numerator and the denominator times the denominator. You will arrive at a new fraction, from there you can simplify into the most tidy form of the fraction.

### How To: Find the slope from a set of points

To find the slope of a line you must have two points and then you must plug in the two points into the slope formula. The slope formula is m= y2-y1 over x2-x1. If the slope is a fraction be sure to reduce to the lowest. Remember if a number is divided into zero it is zero, if zero is divided into the number it is undefined. A calculator can help one remember this. Horizontal lines have slopes and vertical lines do not. Drawing the lines on a graph can help you see the actual slopes and which ...

### How To: Find the standard deviation with the Z-Score formula

In this tutorial, we learn how to find the standard deviation with the Z-Score formula. First, take your problem and write it out one by one underneath each other. Then, you will need to substitute the numbers in for the variables that are in the problem. Once you do this, you will follow the basic rules of math to find out what the answer to the problem is appropriately. Once you have done this, finish off the problem to find the answer, then you will have found the standard deviation using ...

### How To: Solve word problems containing radical equations

See how to unpack and solve a word problem containing radical equations with this free video math lesson from Internet pedagogical superstar Simon Khan. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Complete a proof involving segments

This video from Yay Math! is a geometry lesson on how to complete a proof involving segments. He draws a line segment with four points labeled A, B, C and D. The problem is as follows: Given: AC is equivalent to BD. Prove that AB is equivalent to CD. The first statement of proof is the given. Next, you need to define the congruent segments and state that they're equal in measurement. Next, break down the segments: AC=AB+BC, and BD=BC+CD. This is called segment addition postulate. The end of t...

### How To: Do long division with decimals

Video Nerd thinks that when your doing long division with decimals you should first take out the decimal. Write the number as if it didn't have a decimal. For example if the problem was 12.5 divided by 5 then you will just use 125 and divide that by 5. Next divide the first digit of the dividend by the divisor an write the number up top. Next you multiply, after your done multiplying the numbers subtract, and when your done subtracting the numbers drop the reaming numbers in the dividend down...

### How To: Prove a triangle inscribed in a circle is right angled

When a triangle is inserted in a circle in such a way that one of the side of the triangle is diameter of the circle then the triangle is right triangle. To prove this first draw the figure of a circle. Now draw a diameter to it. It can be any line passing through the center of the circle and touching the sides of it. Now making this as the side of a triangle draw two lines from the ends of the diameter to a point on the circle. Now join the center of the circle to the other vertex of the cir...

### How To: Calculate the height and volume of a pyramid

Need to know how to calculate the height and volume of a pyramid in geometry? Learn how with this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Find the coordinate of a point

In this video the author shows how to plot a point on the coordinate plane. He explains about the coordinate plane and shows how to read and write points to it with an example. He says that any point on the coordinate plane has an x, y- coordinate values. He says that for any point its projection on the x-axis is its x-coordinate and the points projection on y-axis is its y-coordinate. He shows how to find this out for a sample value and plots the coordinates of it. In this video the author u...

### How To: Find the equation of a line given 1 point

Need help figuring out how to find the equation of a line given a single point? Learn how with this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Solve problems involving functions in algebra

Need to know how to solve function problems in algebra? From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to work with and solve functions.

### How To: Cancel out in basic algebra

This video gives you brief tutorial on simplifying expressions, or canceling out common factors. He starts out by answering the question "What is canceling?" and demonstrates a basic example. You find the greatest common factor between the numerator and denominator, which you then divide both by. This can also be done if you have variables in your fraction. He then shows it can be done the same way if you have binomials in your fractions. However, you must be careful that the denominator does...