Question

Gwen was asked to solve 3x^2 - 20 = 7 by factoring using the difference of squares pattern.
What is/are the correct solution(s)?
x = 9, x = -9
x = -3, x = 3
x = 3
x = -3

Answer 1

3x^2 - 20 = 7
=> 3x^2 - 27 = 0
=> 3(x^2 - 9) = 0
=> 3(x - 3)(x + 3) = 0

So x = 3 or x = -3.