X^2-31-90=0

Solution for X^2-31-90=0 equation:

Simplifying
X2 + -31 + -90 = 0

Reorder the terms:
-31 + -90 + X2 = 0

Combine like terms: -31 + -90 = -121
-121 + X2 = 0

Solving
-121 + X2 = 0

Solving for variable 'X'.

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

Add '121' to each side of the equation.
-121 + 121 + X2 = 0 + 121

Combine like terms: -121 + 121 = 0
0 + X2 = 0 + 121
X2 = 0 + 121

Combine like terms: 0 + 121 = 121
X2 = 121

Simplifying
X2 = 121

Take the square root of each side:
X = {-11, 11}