X^2-21+20=

Solution for X^2-21+20= equation:

Simplifying
X2 + -21 + 20 = 0

Reorder the terms:
-21 + 20 + X2 = 0

Combine like terms: -21 + 20 = -1
-1 + X2 = 0

Solving
-1 + X2 = 0

Solving for variable 'X'.

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

Add '1' to each side of the equation.
-1 + 1 + X2 = 0 + 1

Combine like terms: -1 + 1 = 0
0 + X2 = 0 + 1
X2 = 0 + 1

Combine like terms: 0 + 1 = 1
X2 = 1

Simplifying
X2 = 1

Take the square root of each side:
X = {-1, 1}