Question

First box: x + 5, x - 5, x + 10, x - 10Second box: x + 2, x - 2, x + 4, x - 4

Answer 1

`(x-4)(x-5)`

Explanation:

Factor the following trinomial:

`x^2-9x+20`

This can be factored in the form:

`\begin{gathered} (x+a)(x+b) \\ \text{where a and b are two numbers that:} \\ -\text{ Add together to get -9} \\ -\text{ Multiply together to get }20 \end{gathered}`

Hence

`(x-4)(x-5)`