81r^2-25=0

Solution for 81r^2-25=0 equation:

Simplifying
81r2 + -25 = 0

Reorder the terms:
-25 + 81r2 = 0

Solving
-25 + 81r2 = 0

Solving for variable 'r'.

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

Add '25' to each side of the equation.
-25 + 25 + 81r2 = 0 + 25

Combine like terms: -25 + 25 = 0
0 + 81r2 = 0 + 25
81r2 = 0 + 25

Combine like terms: 0 + 25 = 25
81r2 = 25

Divide each side by '81'.
r2 = 0.3086419753

Simplifying
r2 = 0.3086419753

Take the square root of each side:
r = {-0.555555556, 0.555555556}