-6r^2-72r-216=0

Solution for -6r^2-72r-216=0 equation:

Simplifying
-6r2 + -72r + -216 = 0

Reorder the terms:
-216 + -72r + -6r2 = 0

Solving
-216 + -72r + -6r2 = 0

Solving for variable 'r'.

Factor out the Greatest Common Factor (GCF), '-6'.
-6(36 + 12r + r2) = 0

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

Ignore the factor -6.
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 + 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
Solution
r = {-6, -6}