Quadratic equations

Question

The path of a projectile launched from a 16 foot tall tower is modeled by the equation y=-16x^2×64x+16. What is the maximum height, in feet, reached by the projectile?

Answer 1

Your maximum height will be at the vertex which will also be the highest point as this graph points down. We can find the vertex as (-b/2a, f(-b/2a) or the value obtained by putting the line of symmetry in for all X-values in the equation. -b/2a will be -64/2(-16) which is 2. -16(2)^2+64(2)+16 = -64 + 128 + 16 = 64 + 16 = 80. Thus the coordinate for this highest point is (2, 80) so the highest point will be 80 feet above the ground.