.5*x^2-4=0

Solution for .5*x^2-4=0 equation:

Simplifying
0.5x2 + -4 = 0

Reorder the terms:
-4 + 0.5x2 = 0

Solving
-4 + 0.5x2 = 0

Solving for variable 'x'.

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

Add '4' to each side of the equation.
-4 + 4 + 0.5x2 = 0 + 4

Combine like terms: -4 + 4 = 0
0 + 0.5x2 = 0 + 4
0.5x2 = 0 + 4

Combine like terms: 0 + 4 = 4
0.5x2 = 4

Divide each side by '0.5'.
x2 = 8

Simplifying
x2 = 8

Take the square root of each side:
x = {-2.828427125, 2.828427125}