9=c(c-8)

Solution for 9=c(c-8) equation:

Simplifying
9 = c(c + -8)

Reorder the terms:
9 = c(-8 + c)
9 = (-8 * c + c * c)
9 = (-8c + c2)

Solving
9 = -8c + c2

Solving for variable 'c'.

Reorder the terms:
9 + 8c + -1c2 = -8c + 8c + c2 + -1c2

Combine like terms: -8c + 8c = 0
9 + 8c + -1c2 = 0 + c2 + -1c2
9 + 8c + -1c2 = c2 + -1c2

Combine like terms: c2 + -1c2 = 0
9 + 8c + -1c2 = 0

Factor a trinomial.
(9 + -1c)(1 + c) = 0

Subproblem 1
Set the factor '(9 + -1c)' equal to zero and attempt to solve:

Simplifying
9 + -1c = 0

Solving
9 + -1c = 0

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

Add '-9' to each side of the equation.
9 + -9 + -1c = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -1c = 0 + -9
-1c = 0 + -9

Combine like terms: 0 + -9 = -9
-1c = -9

Divide each side by '-1'.
c = 9

Simplifying
c = 9
Subproblem 2
Set the factor '(1 + c)' equal to zero and attempt to solve:

Simplifying
1 + c = 0

Solving
1 + c = 0

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

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

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

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

Simplifying
c = -1
Solution
c = {9, -1}