Chapter 6 - Radical Functions and Rational Exponents - 6-2 Multiplying and Dividing Radical Expressions - Practice and Problem-Solving Exercises - Page 373: 89

$y^2-4y+16-\dfrac{128}{y+4}$

Equating the given divisor, $ y+4 ,$ to zero and then solving for the variable result to \begin{align*} y+4&=0 \\ y&=-4 .\end{align*} Using $ -4 $ in the synthetic division below, then $ (y^3-64)\div(y+4) ,$ is equal to \begin{align*} y^2-4y+16-\dfrac{128}{y+4} .\end{align*}