-r^2=36-12r

Solution for -r^2=36-12r equation:

Simplifying
-1r2 = 36 + -12r

Solving
-1r2 = 36 + -12r

Solving for variable 'r'.

Reorder the terms:
-36 + 12r + -1r2 = 36 + -12r + -36 + 12r

Reorder the terms:
-36 + 12r + -1r2 = 36 + -36 + -12r + 12r

Combine like terms: 36 + -36 = 0
-36 + 12r + -1r2 = 0 + -12r + 12r
-36 + 12r + -1r2 = -12r + 12r

Combine like terms: -12r + 12r = 0
-36 + 12r + -1r2 = 0

Factor a trinomial.
(-6 + r)(6 + -1r) = 0

Subproblem 1
Set the factor '(-6 + r)' equal to zero and attempt to solve:

Simplifying
-6 + r = 0

Solving
-6 + r = 0

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

Add '6' to each side of the equation.
-6 + 6 + r = 0 + 6

Combine like terms: -6 + 6 = 0
0 + r = 0 + 6
r = 0 + 6

Combine like terms: 0 + 6 = 6
r = 6

Simplifying
r = 6
Subproblem 2
Set the factor '(6 + -1r)' equal to zero and attempt to solve:

Simplifying
6 + -1r = 0

Solving
6 + -1r = 0

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

Add '-6' to each side of the equation.
6 + -6 + -1r = 0 + -6

Combine like terms: 6 + -6 = 0
0 + -1r = 0 + -6
-1r = 0 + -6

Combine like terms: 0 + -6 = -6
-1r = -6

Divide each side by '-1'.
r = 6

Simplifying
r = 6
Solution
r = {6, 6}