Answer:
Your other solution is -8
Explanation:
Ignore the 8 for solving and solve it yourself
so how to solve:
x²-64 = 0 <- Rewrite
(x+8)(x-8) = 0 <-Factor (this is a difference of two perfect squares)
x+8 = 0 and x-8=0 <- Get the equations alone and solve
-8 -8 +8 +8
x = -8 and x=8