Question

a shark jumps out the water. Yhe function f(x)=-16x^2+21x models the shark's height, in feet, above the water after x seconds. How longis teh shark out of the water

Answer 1

the peak of the jump lies on the axis of symmetry of the parabola
... x = -b / 2a = -21 / (2 * -16)

time up equals time down

time of flight (jump) = 2 * 21/32