Question

Solve. 7x2 – 63 = 0

Answer 1

factor out 7

7(x^2 - 9) = 0 <---x^2 - 9 is a perfect square so..

7(x+3)(x-3) = 0

now divide both sides by 7

(x+3)(x-3)

now you can equate each factor 0

x + 3 = 0

AND

x - 3 = 0

therefore..x = 3 and x = -3