Question

Solve the following quadratic function by factoring f(x) = x2 – X – 12 Enter the number that belongs in the green box. x = 4; x = [?] Enter

Answer 1

The given function is

`f(x)=x^2-x-12`

To solve it by factoring, we have to look for two numbers whose product is 12 and whose difference is 1. Those numbers are 4 and 3.

`f(x)=(x-4)(x+3)=0`

Then, we use the zero property

`\begin{gathered} x-4=0\rightarrow x=4 \\ x+3=\rightarrow x=-3 \end{gathered}`

Hence, the answer is -3.