81=c^2

Solution for 81=c^2 equation:

Simplifying
81 = c2

Solving
81 = c2

Solving for variable 'c'.

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

Add '-1c2' to each side of the equation.
81 + -1c2 = c2 + -1c2

Combine like terms: c2 + -1c2 = 0
81 + -1c2 = 0

Add '-81' to each side of the equation.
81 + -81 + -1c2 = 0 + -81

Combine like terms: 81 + -81 = 0
0 + -1c2 = 0 + -81
-1c2 = 0 + -81

Combine like terms: 0 + -81 = -81
-1c2 = -81

Divide each side by '-1'.
c2 = 81

Simplifying
c2 = 81

Take the square root of each side:
c = {-9, 9}