Answer
$2x^2-4x-30$
Work Step by Step
Step 1. Based on the given graph, identify zeros $x=-3,5$ and we can write a general form as $y=a(x+3)(x-5)$
Step 2. As $(0,-30)$ is on the curve, we have $-30=a(3)(-5)$, thus $a=2$
Step 3. Thus function is $y=f(x)=2(x+3)(x-5)=2(x^2-2x-15)=2x^2-4x-30$
