Question

How do you factor the expressions `x^2 - 16x + 63 = 0`?

Answer 1

`(x-7)(x-9) = 0`

Explanation:

In general:

`(x-a)(x-b) = x^2-(a+b)+ab`

We find `63 = 7 xx 9` and `16 = 7 + 9`, so:

`x^2-16x+63 = (x-7)(x-9)`