12=4x^2-x^2

Solution for 12=4x^2-x^2 equation:

Simplifying
12 = 4x2 + -1x2

Combine like terms: 4x2 + -1x2 = 3x2
12 = 3x2

Solving
12 = 3x2

Solving for variable 'x'.

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

Add '-3x2' to each side of the equation.
12 + -3x2 = 3x2 + -3x2

Combine like terms: 3x2 + -3x2 = 0
12 + -3x2 = 0

Add '-12' to each side of the equation.
12 + -12 + -3x2 = 0 + -12

Combine like terms: 12 + -12 = 0
0 + -3x2 = 0 + -12
-3x2 = 0 + -12

Combine like terms: 0 + -12 = -12
-3x2 = -12

Divide each side by '-3'.
x2 = 4

Simplifying
x2 = 4

Take the square root of each side:
x = {-2, 2}