This video shows the method to add rational expressions with different denominators. The first step in this process involves finding the LCD. After this is done, the numerator and denominator are multiplied by a specific number so that the fractions are rewritten with common denominators. In the second step the numerators are added or subtracted according to the problem with LCD in the denominator. Simplify the numerator by adding or subtracting like terms. After this, we get a rational expression with simplified numerator and LCD in the denominator. We take the factors which are common in both numerator and denominator. We cancel these common factors to arrive at the final result.