2*x*x-8=42

Solution for 2*x*x-8=42 equation:

Simplifying
2x * x + -8 = 42

Multiply x * x
2x2 + -8 = 42

Reorder the terms:
-8 + 2x2 = 42

Solving
-8 + 2x2 = 42

Solving for variable 'x'.

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

Add '8' to each side of the equation.
-8 + 8 + 2x2 = 42 + 8

Combine like terms: -8 + 8 = 0
0 + 2x2 = 42 + 8
2x2 = 42 + 8

Combine like terms: 42 + 8 = 50
2x2 = 50

Divide each side by '2'.
x2 = 25

Simplifying
x2 = 25

Take the square root of each side:
x = {-5, 5}