Multiply & divide rational expressions

**Divide the following rational expressions and simplify the result.** $\dfrac{2y^3-10y^2-48y}{3y-24}\div\dfrac{y^2+5y+6}{9y^4+18y^3}=$ [[☃ expression 1]] **Which values of $y$ make the resulting expression undefined?** [[☃ radio 1]]