The equation h(t) = −16t^2 + 115t + 15 gives the height of a toy rocket, in feet, t seconds after it is launched from a platform. what is the height of the platform?

Given that the height of the rocket at time t after it was launched is given by:
h(t)=-16t^2+115t+15
the height of the platform which the rocket was launched from will be given by the intercept of h(t), at the intercept, t=0 thus plugging t=0 in the function we get:
h(0)=-16(0)^2+115(0)+15
h(0)=15

hence the height of the platform is 15 ft