Question

How do you solve `x^2 - 8x - 20 = 0`?

Answer 1

x = 10 , x = - 2

Explanation:

first factor the quadratic by considering the factors of - 20 which sum to - 8.
These are - 10 and +2

`rArr x^2 - 8x - 20 = (x - 10 )(x + 2 ) = 0`

hence (x - 10 ) = 0 `rArr x = 10 " or " (x + 2 ) = 0 rArr x = - 2`