(c-12)c-15=30

Solution for (c-12)c-15=30 equation:

Simplifying
(c + -12) * c + -15 = 30

Reorder the terms:
(-12 + c) * c + -15 = 30

Reorder the terms for easier multiplication:
c(-12 + c) + -15 = 30
(-12 * c + c * c) + -15 = 30
(-12c + c2) + -15 = 30

Reorder the terms:
-15 + -12c + c2 = 30

Solving
-15 + -12c + c2 = 30

Solving for variable 'c'.

Reorder the terms:
-15 + -30 + -12c + c2 = 30 + -30

Combine like terms: -15 + -30 = -45
-45 + -12c + c2 = 30 + -30

Combine like terms: 30 + -30 = 0
-45 + -12c + c2 = 0

Factor a trinomial.
(-3 + -1c)(15 + -1c) = 0

Subproblem 1
Set the factor '(-3 + -1c)' equal to zero and attempt to solve:

Simplifying
-3 + -1c = 0

Solving
-3 + -1c = 0

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

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

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

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

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

Simplifying
c = -3
Subproblem 2
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
Solution
c = {-3, 15}