How to Simplify algebraic equations w/ the minus-one trick

Just follow a few steps to simplify algebra with the minus one trick. First step is to take two algebraic equations with having numerator and denominator algebraic equations. Second step is to divide the denominator with numerator. For example, it have like -c/c, it gives like answer as -1, but we have another type like (c-a)/(a-c) - to solve these types of steps, like multiply numerator with minus(-), it gives the common the minus and -(a-c)/(a-c), then it gives -1 as a answer.