SAT math practice question: Parabolas and intersections

 
Try the following SAT math practice question (No Calculator) that tests your understanding of parabolas and intersections in the $xy-$plane.

$$ h(x) = -2(x-3)^2 + 50 $$
In the $xy-$plane, the graph of the quadratic function $h(x)$ intersects the $x-$axis at the points $(a, 0)$ and $(b, 0)$, where $a$ and $b$ are constants. What is the value of $a+b$?

1. $\quad -10$
2. $\quad -6$
3. $\quad 6$
4. $\quad 10$