x^2=2x^2-81

Solution for x^2=2x^2-81 equation:

Simplifying
x2 = 2x2 + -81

Reorder the terms:
x2 = -81 + 2x2

Solving
x2 = -81 + 2x2

Solving for variable 'x'.

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

Add '-2x2' to each side of the equation.
x2 + -2x2 = -81 + 2x2 + -2x2

Combine like terms: x2 + -2x2 = -1x2
-1x2 = -81 + 2x2 + -2x2

Combine like terms: 2x2 + -2x2 = 0
-1x2 = -81 + 0
-1x2 = -81

Divide each side by '-1'.
x2 = 81

Simplifying
x2 = 81

Take the square root of each side:
x = {-9, 9}