r^2-72r+720=0

Solution for r^2-72r+720=0 equation:

Simplifying
r2 + -72r + 720 = 0

Reorder the terms:
720 + -72r + r2 = 0

Solving
720 + -72r + r2 = 0

Solving for variable 'r'.

Factor a trinomial.
(12 + -1r)(60 + -1r) = 0

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

Simplifying
12 + -1r = 0

Solving
12 + -1r = 0

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

Add '-12' to each side of the equation.
12 + -12 + -1r = 0 + -12

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

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

Divide each side by '-1'.
r = 12

Simplifying
r = 12
Subproblem 2
Set the factor '(60 + -1r)' equal to zero and attempt to solve:

Simplifying
60 + -1r = 0

Solving
60 + -1r = 0

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

Add '-60' to each side of the equation.
60 + -60 + -1r = 0 + -60

Combine like terms: 60 + -60 = 0
0 + -1r = 0 + -60
-1r = 0 + -60

Combine like terms: 0 + -60 = -60
-1r = -60

Divide each side by '-1'.
r = 60

Simplifying
r = 60
Solution
r = {12, 60}