This week in Precal 11 we learned on how to solve quadratic equations using factoring, and completing the square method – which can be used when the equation cannot be factored. So, in this post, I will show how to do the completing the square method.

Primarily, we must determine whether an equation can possibly be factored since it is much easier to do so rather than doing the alternative method. We can determine when a quadratic equation is factorable when the product of c (constant) doesn’t sum up to b (middle term). For example:

First step is to multiply ($x^2$) by the constant number which is (-22). Then, we would find the factors of $-22x^2$ to try and find factors that sum up to -9x. And from there, we would just continue doing the factoring method without having to do the harder and alternative method which is making the equation into a perfect square trinomial.

If the quadratic equation is not factorable, then completing the square method will be used to solve the two solutions.

Published inMath 11