3x^2-12=42

Solution for 3x^2-12=42 equation:

Simplifying
3x2 + -12 = 42

Reorder the terms:
-12 + 3x2 = 42

Solving
-12 + 3x2 = 42

Solving for variable 'x'.

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

Add '12' to each side of the equation.
-12 + 12 + 3x2 = 42 + 12

Combine like terms: -12 + 12 = 0
0 + 3x2 = 42 + 12
3x2 = 42 + 12

Combine like terms: 42 + 12 = 54
3x2 = 54

Divide each side by '3'.
x2 = 18

Simplifying
x2 = 18

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