.5=.0021*x^2

Solution for .5=.0021*x^2 equation:

Simplifying
0.5 = 0.0021x2

Solving
0.5 = 0.0021x2

Solving for variable 'x'.

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

Add '-0.0021x2' to each side of the equation.
0.5 + -0.0021x2 = 0.0021x2 + -0.0021x2

Combine like terms: 0.0021x2 + -0.0021x2 = 0.0000
0.5 + -0.0021x2 = 0.0000

Add '-0.5' to each side of the equation.
0.5 + -0.5 + -0.0021x2 = 0.0000 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + -0.0021x2 = 0.0000 + -0.5
-0.0021x2 = 0.0000 + -0.5

Combine like terms: 0.0000 + -0.5 = -0.5
-0.0021x2 = -0.5

Divide each side by '-0.0021'.
x2 = 238.0952381

Simplifying
x2 = 238.0952381

Take the square root of each side:
x = {-15.430334996, 15.430334996}