81u^2-64=0

Solution for 81u^2-64=0 equation:

Simplifying
81u2 + -64 = 0

Reorder the terms:
-64 + 81u2 = 0

Solving
-64 + 81u2 = 0

Solving for variable 'u'.

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

Add '64' to each side of the equation.
-64 + 64 + 81u2 = 0 + 64

Combine like terms: -64 + 64 = 0
0 + 81u2 = 0 + 64
81u2 = 0 + 64

Combine like terms: 0 + 64 = 64
81u2 = 64

Divide each side by '81'.
u2 = 0.7901234568

Simplifying
u2 = 0.7901234568

Take the square root of each side:
u = {-0.888888889, 0.888888889}