x(x)-400=0

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

Simplifying
x(x) + -400 = 0

Multiply x * x
x2 + -400 = 0

Reorder the terms:
-400 + x2 = 0

Solving
-400 + x2 = 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 + x2 = 0 + 400

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

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

Simplifying
x2 = 400

Take the square root of each side:
x = {-20, 20}