3x^2-18=x^2

Solution for 3x^2-18=x^2 equation:

Simplifying
3x2 + -18 = x2

Reorder the terms:
-18 + 3x2 = x2

Solving
-18 + 3x2 = x2

Solving for variable 'x'.

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

Add '-1x2' to each side of the equation.
-18 + 3x2 + -1x2 = x2 + -1x2

Combine like terms: 3x2 + -1x2 = 2x2
-18 + 2x2 = x2 + -1x2

Combine like terms: x2 + -1x2 = 0
-18 + 2x2 = 0

Add '18' to each side of the equation.
-18 + 18 + 2x2 = 0 + 18

Combine like terms: -18 + 18 = 0
0 + 2x2 = 0 + 18
2x2 = 0 + 18

Combine like terms: 0 + 18 = 18
2x2 = 18

Divide each side by '2'.
x2 = 9

Simplifying
x2 = 9

Take the square root of each side:
x = {-3, 3}