81x^2-216=0

Solution for 81x^2-216=0 equation:

Simplifying
81x2 + -216 = 0

Reorder the terms:
-216 + 81x2 = 0

Solving
-216 + 81x2 = 0

Solving for variable 'x'.

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

Add '216' to each side of the equation.
-216 + 216 + 81x2 = 0 + 216

Combine like terms: -216 + 216 = 0
0 + 81x2 = 0 + 216
81x2 = 0 + 216

Combine like terms: 0 + 216 = 216
81x2 = 216

Divide each side by '81'.
x2 = 2.666666667

Simplifying
x2 = 2.666666667

Take the square root of each side:
x = {-1.632993162, 1.632993162}