(x+4)(x-4)=9

Solution for (x+4)(x-4)=9 equation:

Simplifying
(x + 4)(x + -4) = 9

Reorder the terms:
(4 + x)(x + -4) = 9

Reorder the terms:
(4 + x)(-4 + x) = 9

Multiply (4 + x) * (-4 + x)
(4(-4 + x) + x(-4 + x)) = 9
((-4 * 4 + x * 4) + x(-4 + x)) = 9
((-16 + 4x) + x(-4 + x)) = 9
(-16 + 4x + (-4 * x + x * x)) = 9
(-16 + 4x + (-4x + x2)) = 9

Combine like terms: 4x + -4x = 0
(-16 + 0 + x2) = 9
(-16 + x2) = 9

Solving
-16 + x2 = 9

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 = 9 + 16

Combine like terms: -16 + 16 = 0
0 + x2 = 9 + 16
x2 = 9 + 16

Combine like terms: 9 + 16 = 25
x2 = 25

Simplifying
x2 = 25

Take the square root of each side:
x = {-5, 5}