(x+6)(x-6)-51=0

Solution for (x+6)(x-6)-51=0 equation:

Simplifying
(x + 6)(x + -6) + -51 = 0

Reorder the terms:
(6 + x)(x + -6) + -51 = 0

Reorder the terms:
(6 + x)(-6 + x) + -51 = 0

Multiply (6 + x) * (-6 + x)
(6(-6 + x) + x(-6 + x)) + -51 = 0
((-6 * 6 + x * 6) + x(-6 + x)) + -51 = 0
((-36 + 6x) + x(-6 + x)) + -51 = 0
(-36 + 6x + (-6 * x + x * x)) + -51 = 0
(-36 + 6x + (-6x + x2)) + -51 = 0

Combine like terms: 6x + -6x = 0
(-36 + 0 + x2) + -51 = 0
(-36 + x2) + -51 = 0

Reorder the terms:
-36 + -51 + x2 = 0

Combine like terms: -36 + -51 = -87
-87 + x2 = 0

Solving
-87 + x2 = 0

Solving for variable 'x'.

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

Add '87' to each side of the equation.
-87 + 87 + x2 = 0 + 87

Combine like terms: -87 + 87 = 0
0 + x2 = 0 + 87
x2 = 0 + 87

Combine like terms: 0 + 87 = 87
x2 = 87

Simplifying
x2 = 87

Take the square root of each side:
x = {-9.327379053, 9.327379053}