Question

For the function f (x) = x^2 - 2x - 8, find the two points x when f (x) =7

Answer 1

Explanation:

`{x}^(2) - 2x - 8 = 7`

`{x}^(2) - 2x - 8 - 7 = 0`

`{x}^(2) - 2x - 15 = 0`

`{x}^(2) - 5x + 3x - 15 = 0`

`x(x - 5) + 3(x - 5) = 0`

`(x - 5)(x + 3) = 0`

`x = 5 \: \: or \: \: x = - 3`