c^2+9c=90

Solution for c^2+9c=90 equation:

Simplifying
c2 + 9c = 90

Reorder the terms:
9c + c2 = 90

Solving
9c + c2 = 90

Solving for variable 'c'.

Reorder the terms:
-90 + 9c + c2 = 90 + -90

Combine like terms: 90 + -90 = 0
-90 + 9c + c2 = 0

Factor a trinomial.
(-15 + -1c)(6 + -1c) = 0

Subproblem 1
Set the factor '(-15 + -1c)' equal to zero and attempt to solve:

Simplifying
-15 + -1c = 0

Solving
-15 + -1c = 0

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

Add '15' to each side of the equation.
-15 + 15 + -1c = 0 + 15

Combine like terms: -15 + 15 = 0
0 + -1c = 0 + 15
-1c = 0 + 15

Combine like terms: 0 + 15 = 15
-1c = 15

Divide each side by '-1'.
c = -15

Simplifying
c = -15
Subproblem 2
Set the factor '(6 + -1c)' equal to zero and attempt to solve:

Simplifying
6 + -1c = 0

Solving
6 + -1c = 0

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

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

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

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

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

Simplifying
c = 6
Solution
c = {-15, 6}