0.9=4*x^2

Solution for 0.9=4*x^2 equation:

Simplifying
0.9 = 4x2

Solving
0.9 = 4x2

Solving for variable 'x'.

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

Add '-4x2' to each side of the equation.
0.9 + -4x2 = 4x2 + -4x2

Combine like terms: 4x2 + -4x2 = 0
0.9 + -4x2 = 0

Add '-0.9' to each side of the equation.
0.9 + -0.9 + -4x2 = 0 + -0.9

Combine like terms: 0.9 + -0.9 = 0.0
0.0 + -4x2 = 0 + -0.9
-4x2 = 0 + -0.9

Combine like terms: 0 + -0.9 = -0.9
-4x2 = -0.9

Divide each side by '-4'.
x2 = 0.225

Simplifying
x2 = 0.225

Take the square root of each side:
x = {-0.474341649, 0.474341649}