X*X+20*20=21*21

Solution for X*X+20*20=21*21 equation:

Simplifying
X * X + 20 * 20 = 21 * 21

Multiply X * X
X2 + 20 * 20 = 21 * 21

Multiply 20 * 20
X2 + 400 = 21 * 21

Reorder the terms:
400 + X2 = 21 * 21

Multiply 21 * 21
400 + X2 = 441

Solving
400 + X2 = 441

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 = 441 + -400

Combine like terms: 400 + -400 = 0
0 + X2 = 441 + -400
X2 = 441 + -400

Combine like terms: 441 + -400 = 41
X2 = 41

Simplifying
X2 = 41

Take the square root of each side:
X = {-6.403124237, 6.403124237}