Problem: how do you solve 6csquared-5c-6?
I don't understand this problem at all.
These are usually set to zero in order to solve them.
6c^2 - 5c - 6 = 0
(3c + 2)(2c - 3) = 0 cross multiplying gives -9c + 4c = -5c
One, or both, of the factors must equal zero.
Solve both.
(3c + 2) = 0
3c = -2
c = -2/3
(2c - 3) = 0
2c = 3
c = 3/2
Answer: c = 3/2 and c = -2/3