-3r(4r-8)=-36

Solution for -3r(4r-8)=-36 equation:

Simplifying
-3r(4r + -8) = -36

Reorder the terms:
-3r(-8 + 4r) = -36
(-8 * -3r + 4r * -3r) = -36
(24r + -12r2) = -36

Solving
24r + -12r2 = -36

Solving for variable 'r'.

Reorder the terms:
36 + 24r + -12r2 = -36 + 36

Combine like terms: -36 + 36 = 0
36 + 24r + -12r2 = 0

Factor out the Greatest Common Factor (GCF), '12'.
12(3 + 2r + -1r2) = 0

Factor a trinomial.
12((3 + -1r)(1 + r)) = 0

Ignore the factor 12.
Subproblem 1
Set the factor '(3 + -1r)' equal to zero and attempt to solve:

Simplifying
3 + -1r = 0

Solving
3 + -1r = 0

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

Add '-3' to each side of the equation.
3 + -3 + -1r = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -1r = 0 + -3
-1r = 0 + -3

Combine like terms: 0 + -3 = -3
-1r = -3

Divide each side by '-1'.
r = 3

Simplifying
r = 3
Subproblem 2
Set the factor '(1 + r)' equal to zero and attempt to solve:

Simplifying
1 + r = 0

Solving
1 + r = 0

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

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

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

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

Simplifying
r = -1
Solution
r = {3, -1}