4c^2-21c-18=0

Solution for 4c^2-21c-18=0 equation:

Simplifying
4c2 + -21c + -18 = 0

Reorder the terms:
-18 + -21c + 4c2 = 0

Solving
-18 + -21c + 4c2 = 0

Solving for variable 'c'.

Factor a trinomial.
(-3 + -4c)(6 + -1c) = 0

Subproblem 1
Set the factor '(-3 + -4c)' equal to zero and attempt to solve:

Simplifying
-3 + -4c = 0

Solving
-3 + -4c = 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 + -4c = 0 + 3

Combine like terms: -3 + 3 = 0
0 + -4c = 0 + 3
-4c = 0 + 3

Combine like terms: 0 + 3 = 3
-4c = 3

Divide each side by '-4'.
c = -0.75

Simplifying
c = -0.75
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 = {-0.75, 6}