x^2+9-81=0

Solution for x^2+9-81=0 equation:

Simplifying
x2 + 9 + -81 = 0

Reorder the terms:
9 + -81 + x2 = 0

Combine like terms: 9 + -81 = -72
-72 + x2 = 0

Solving
-72 + x2 = 0

Solving for variable 'x'.

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

Add '72' to each side of the equation.
-72 + 72 + x2 = 0 + 72

Combine like terms: -72 + 72 = 0
0 + x2 = 0 + 72
x2 = 0 + 72

Combine like terms: 0 + 72 = 72
x2 = 72

Simplifying
x2 = 72

Take the square root of each side:
x = {-8.485281374, 8.485281374}