Answer:
It will take the bird 3.61 seconds to reach a height of 40.
Explanation:
You have:
H=-16t²+55t+50
where H is the height of the bird and t is the amount of time, in seconds, the bird has been in the air.
To know the time it will take for the bird to reach a height of 40, you must replace the height H with 40:
40=-16t²+55t+50
Then:
0= -16t²+55t+50-40
0=-16t²+55t+10
Being a quadratic function of the form 0 = A * x + B * x + C, to calculate the values of x the expression can be applied:
In this case, being A = -16, B = 55 and C = 10 and replacing, the values are obtained: t1 = 3.61 and t2 = -0.173. Since time cannot be negative, it will take the bird 3.61 seconds to reach a height of 40.