Question

which are we looking for? x at vertex - y at vertex - positive zero. sally threw a ball in the air. sallys friend wanted to find out how high the ball got given that it took 1 second to get to its highest point.

Explanation:

The problem is about finding the height of a ball, which corresponds to the y - value at the vertex of the ball's trajectory (a parabolic path in physics, modeled by a quadratic function in math). Since Sally's friend wants to know how high the ball got, we are looking for the y - value at the vertex.

Answer:

y at the vertex