(x+1)(x-1)=8

Solution for (x+1)(x-1)=8 equation:

Simplifying
(x + 1)(x + -1) = 8

Reorder the terms:
(1 + x)(x + -1) = 8

Reorder the terms:
(1 + x)(-1 + x) = 8

Multiply (1 + x) * (-1 + x)
(1(-1 + x) + x(-1 + x)) = 8
((-1 * 1 + x * 1) + x(-1 + x)) = 8
((-1 + 1x) + x(-1 + x)) = 8
(-1 + 1x + (-1 * x + x * x)) = 8
(-1 + 1x + (-1x + x2)) = 8

Combine like terms: 1x + -1x = 0
(-1 + 0 + x2) = 8
(-1 + x2) = 8

Solving
-1 + x2 = 8

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '1' to each side of the equation.
-1 + 1 + x2 = 8 + 1

Combine like terms: -1 + 1 = 0
0 + x2 = 8 + 1
x2 = 8 + 1

Combine like terms: 8 + 1 = 9
x2 = 9

Simplifying
x2 = 9

Take the square root of each side:
x = {-3, 3}