(x+3)(x-3)-16=0

Solution for (x+3)(x-3)-16=0 equation:

Simplifying
(x + 3)(x + -3) + -16 = 0

Reorder the terms:
(3 + x)(x + -3) + -16 = 0

Reorder the terms:
(3 + x)(-3 + x) + -16 = 0

Multiply (3 + x) * (-3 + x)
(3(-3 + x) + x(-3 + x)) + -16 = 0
((-3 * 3 + x * 3) + x(-3 + x)) + -16 = 0
((-9 + 3x) + x(-3 + x)) + -16 = 0
(-9 + 3x + (-3 * x + x * x)) + -16 = 0
(-9 + 3x + (-3x + x2)) + -16 = 0

Combine like terms: 3x + -3x = 0
(-9 + 0 + x2) + -16 = 0
(-9 + x2) + -16 = 0

Reorder the terms:
-9 + -16 + x2 = 0

Combine like terms: -9 + -16 = -25
-25 + x2 = 0

Solving
-25 + x2 = 0

Solving for variable 'x'.

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

Add '25' to each side of the equation.
-25 + 25 + x2 = 0 + 25

Combine like terms: -25 + 25 = 0
0 + x2 = 0 + 25
x2 = 0 + 25

Combine like terms: 0 + 25 = 25
x2 = 25

Simplifying
x2 = 25

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