Answer
$y=\frac{1}{2}(x+1)(x-1)(x-2)$
Work Step by Step
Step 1. Find zeros $x=-1,1,2$ (multiplicity 1).
Step 2. Write a general form $y=a(x+1)(x-1)(x-2), a\lt0$.
Step 3. Use point $(0,-1)$, $-1=a(0+1)(0-1)(0-2)$, we have $a=\frac{1}{2}$
Step 4. Provide the answer $y=\frac{1}{2}(x+1)(x-1)(x-2)$
