15c^2-17c-42=0

Solution for 15c^2-17c-42=0 equation:

Simplifying
15c2 + -17c + -42 = 0

Reorder the terms:
-42 + -17c + 15c2 = 0

Solving
-42 + -17c + 15c2 = 0

Solving for variable 'c'.

Factor a trinomial.
(-6 + -5c)(7 + -3c) = 0

Subproblem 1
Set the factor '(-6 + -5c)' equal to zero and attempt to solve:

Simplifying
-6 + -5c = 0

Solving
-6 + -5c = 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 + -5c = 0 + 6

Combine like terms: -6 + 6 = 0
0 + -5c = 0 + 6
-5c = 0 + 6

Combine like terms: 0 + 6 = 6
-5c = 6

Divide each side by '-5'.
c = -1.2

Simplifying
c = -1.2
Subproblem 2
Set the factor '(7 + -3c)' equal to zero and attempt to solve:

Simplifying
7 + -3c = 0

Solving
7 + -3c = 0

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

Add '-7' to each side of the equation.
7 + -7 + -3c = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -3c = 0 + -7
-3c = 0 + -7

Combine like terms: 0 + -7 = -7
-3c = -7

Divide each side by '-3'.
c = 2.333333333

Simplifying
c = 2.333333333
Solution
c = {-1.2, 2.333333333}