Answer
$y=\frac{1}{5}(x+4)(x+1)^2(x-3)$.
Work Step by Step
Step 1. Find zeros $x=-4,3$ (multiplicity 1), $x=-1$ (multiplicity 2).
Step 2. Write a general form $y=a(x+4)(x+1)^2(x-3)$.
Step 3. Use point $(1,-8)$, $-8=a(1+4)(1+1)^2(1-3)$, we have $a=\frac{1}{5}$
Step 4. Provide the answer $y=\frac{1}{5}(x+4)(x+1)^2(x-3)$.
