(x+1)(x-1)=80

Solution for (x+1)(x-1)=80 equation:

Simplifying
(x + 1)(x + -1) = 80

Reorder the terms:
(1 + x)(x + -1) = 80

Reorder the terms:
(1 + x)(-1 + x) = 80

Multiply (1 + x) * (-1 + x)
(1(-1 + x) + x(-1 + x)) = 80
((-1 * 1 + x * 1) + x(-1 + x)) = 80
((-1 + 1x) + x(-1 + x)) = 80
(-1 + 1x + (-1 * x + x * x)) = 80
(-1 + 1x + (-1x + x2)) = 80

Combine like terms: 1x + -1x = 0
(-1 + 0 + x2) = 80
(-1 + x2) = 80

Solving
-1 + x2 = 80

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 = 80 + 1

Combine like terms: -1 + 1 = 0
0 + x2 = 80 + 1
x2 = 80 + 1

Combine like terms: 80 + 1 = 81
x2 = 81

Simplifying
x2 = 81

Take the square root of each side:
x = {-9, 9}