Some fireworks are fired vertically into the air from the ground at an initial velocity of 80 feet per second. This motion can be modeled by the quadratic equation s(t) = -16t^2 + 80t. If a problem asks you to find how high the firework can go (this is the point where it explodes), what are they asking you for? (a) x coordinate of the vertex (b) y coordinate of the vertex (C) x coordinate of the roots (d) y coordinate of the roots