(x+3)(x-3)=18

Solution for (x+3)(x-3)=18 equation:

Simplifying
(x + 3)(x + -3) = 18

Reorder the terms:
(3 + x)(x + -3) = 18

Reorder the terms:
(3 + x)(-3 + x) = 18

Multiply (3 + x) * (-3 + x)
(3(-3 + x) + x(-3 + x)) = 18
((-3 * 3 + x * 3) + x(-3 + x)) = 18
((-9 + 3x) + x(-3 + x)) = 18
(-9 + 3x + (-3 * x + x * x)) = 18
(-9 + 3x + (-3x + x2)) = 18

Combine like terms: 3x + -3x = 0
(-9 + 0 + x2) = 18
(-9 + x2) = 18

Solving
-9 + x2 = 18

Solving for variable 'x'.

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

Add '9' to each side of the equation.
-9 + 9 + x2 = 18 + 9

Combine like terms: -9 + 9 = 0
0 + x2 = 18 + 9
x2 = 18 + 9

Combine like terms: 18 + 9 = 27
x2 = 27

Simplifying
x2 = 27

Take the square root of each side:
x = {-5.196152423, 5.196152423}