5x^2-81=0

Solution for 5x^2-81=0 equation:

Simplifying
5x2 + -81 = 0

Reorder the terms:
-81 + 5x2 = 0

Solving
-81 + 5x2 = 0

Solving for variable 'x'.

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

Add '81' to each side of the equation.
-81 + 81 + 5x2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + 5x2 = 0 + 81
5x2 = 0 + 81

Combine like terms: 0 + 81 = 81
5x2 = 81

Divide each side by '5'.
x2 = 16.2

Simplifying
x2 = 16.2

Take the square root of each side:
x = {-4.02492236, 4.02492236}