x*x-18=0

Solution for x*x-18=0 equation:

Simplifying
x * x + -18 = 0

Multiply x * x
x2 + -18 = 0

Reorder the terms:
-18 + x2 = 0

Solving
-18 + x2 = 0

Solving for variable 'x'.

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

Add '18' to each side of the equation.
-18 + 18 + x2 = 0 + 18

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

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

Simplifying
x2 = 18

Take the square root of each side:
x = {-4.242640687, 4.242640687}