Chapter 7 - Polynomial Equations and Factoring - 7.4 - Solving Polynomial Equations in Factored Form - Exercises - Page 381: 19

The solutions are $c=3$, $c=-1$ and $c=6$.

Given: $(15-5c)(5c+5)(-c+6)=0$ Using zero-product property, we have $15-5c=0$ or $5c+5=0$ or $-c+6=0$ Solving for $c$, we get $c=\frac{15}{5}=3$ or $c=\frac{-5}{5}=-1$ or $c=6$. The roots are $c=3$, $c=-1$ and $c=6$.