Question

Factor completely. 5x2 - 45 5(x + 3)(x - 3) 5(x2 - 45) 5(x - 9)(x + 9) (5x + 9)(x - 5)

Answer 1

`5x^2 - 45 = 5(x^2 - 9) = 5(x^2 - 3^2) = 5(x - 3) (x + 3)`


Answer: 5(x - 3) (x + 3)

Answer 2

Option A is correct

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

Explanation:

Using identity rule:

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

To factor completely:

`5x^2-45`

Take 5 common out we have;

`5(x^2-9)`

Apply the identity rule

then;

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

Therefore, the complete factored of the given equation is:
`5(x+3)(x-3)`