Answer:
a) No. t < 0 is not part of the useful domain of the function
b) 2.0 seconds
Step-by-step explanation:
a) A graph of the function is shown below. It shows t-intercepts at t=-0.25 and t=2.0. We presume that t is measured forward from some event such as the ball being thrown or hit. The model's predicted ball location has no meaning prior to that event, when values of t are negative.
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b) It is convenient to use a graphing calculator to find the t-intercepts. Or, the equation can be solved for h=0 any of several ways algebraically. One is by factoring.
h = 0 = -16t² +28t +8 . . . . . . . . . . . . the ball hits the ground when h = 0
0 = -4(4t² -7t -2) = -4(4t +1)(t -2)
This has t-intercepts where the factors are zero, at t=-1/4 and t=2.
The ball will hit the ground after 2 seconds.
20t +15t+90+25t-75=60t+15
60t+15/3=20t+5 as the average
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Answer:
-7/45
Step-by-step explanation:
First, find the lowest common denominator for 9 and 15. It's 45. Make both fractions over 45 by multiplying the top and bottom by the same number.

Since 15*3=45, multiply the top by 3 also. Since 9*5=45, multiply the top by 5 also.

Combine the fractions
Answer in lowest terms
9514 1404 393
Answer:
{-8, -4, -2, -1, 1, 2, 4, 8}
Step-by-step explanation:
Possible rational roots are positive and negative divisors of the constant 8:
{-8, -4, -2, -1, 1, 2, 4, 8}
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<em>Additional comment</em>
This polynomial has no rational roots. Its two real roots are both negative and irrational.