(x-4)(x+4)=20

Solution for (x-4)(x+4)=20 equation:

Simplifying
(x + -4)(x + 4) = 20

Reorder the terms:
(-4 + x)(x + 4) = 20

Reorder the terms:
(-4 + x)(4 + x) = 20

Multiply (-4 + x) * (4 + x)
(-4(4 + x) + x(4 + x)) = 20
((4 * -4 + x * -4) + x(4 + x)) = 20
((-16 + -4x) + x(4 + x)) = 20
(-16 + -4x + (4 * x + x * x)) = 20
(-16 + -4x + (4x + x2)) = 20

Combine like terms: -4x + 4x = 0
(-16 + 0 + x2) = 20
(-16 + x2) = 20

Solving
-16 + x2 = 20

Solving for variable 'x'.

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

Add '16' to each side of the equation.
-16 + 16 + x2 = 20 + 16

Combine like terms: -16 + 16 = 0
0 + x2 = 20 + 16
x2 = 20 + 16

Combine like terms: 20 + 16 = 36
x2 = 36

Simplifying
x2 = 36

Take the square root of each side:
x = {-6, 6}