r^2-9r=0

Solution for r^2-9r=0 equation:

Simplifying
r2 + -9r = 0

Reorder the terms:
-9r + r2 = 0

Solving
-9r + r2 = 0

Solving for variable 'r'.

Factor out the Greatest Common Factor (GCF), 'r'.
r(-9 + r) = 0

Subproblem 1
Set the factor 'r' equal to zero and attempt to solve:

Simplifying
r = 0

Solving
r = 0

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

Simplifying
r = 0
Subproblem 2
Set the factor '(-9 + r)' equal to zero and attempt to solve:

Simplifying
-9 + r = 0

Solving
-9 + r = 0

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

Add '9' to each side of the equation.
-9 + 9 + r = 0 + 9

Combine like terms: -9 + 9 = 0
0 + r = 0 + 9
r = 0 + 9

Combine like terms: 0 + 9 = 9
r = 9

Simplifying
r = 9
Solution
r = {0, 9}