Question

The height, in feet, of a t-shirt launched from a t-shirt cannon high in the stands at a football stadium is given by h(x)=-16x^2+64x+80, where x is the time in seconds after the t-shirt is launched. How long will it take for the t-shirt to reach the ground?

Answer 1

Answer:

5 seconds.

Step-by-step explanation:

The first thing we can do is convert h(x) into 0. -16x²+64x+80=0

Then, factor out -16, as both 64 and 80 are divisible by 16.

This leaves you with x²-4x-5=0.

Then, you factor that expression to get (x+1)(x-5).

Convert those to x+1=0 and x-5=0.

Your answers will be x= -1 and x= 5, but since we cannot have a negative time, 5 is the only correct option.