x(4x)-400=0

Solution for x(4x)-400=0 equation:

Simplifying
x(4x) + -400 = 0

Remove parenthesis around (4x)
x * 4x + -400 = 0

Reorder the terms for easier multiplication:
4x * x + -400 = 0

Multiply x * x
4x2 + -400 = 0

Reorder the terms:
-400 + 4x2 = 0

Solving
-400 + 4x2 = 0

Solving for variable 'x'.

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

Add '400' to each side of the equation.
-400 + 400 + 4x2 = 0 + 400

Combine like terms: -400 + 400 = 0
0 + 4x2 = 0 + 400
4x2 = 0 + 400

Combine like terms: 0 + 400 = 400
4x2 = 400

Divide each side by '4'.
x2 = 100

Simplifying
x2 = 100

Take the square root of each side:
x = {-10, 10}