The function
[tex]f(t)= { - 18t}^{2} +42t+36 [/tex]
represents the height of thr path traced by an airborne flying disc, where t is the time in seconds. How many seconds will it take the flying disc to complete its path

Respuesta :

Answer:

3 seconds.

Step-by-step explanation:

f(t) = height of the disc = -18t^2 + 42t + 36.

This equals zero when it completes its path, so:

-18t^2 + 42t + 36 = 0

-6(3t^2 - 7t - 6) = 0

-6 (3t + 2)(t - 3) = 0

t = 3 seconds  (We ignore the negative zero).