An object is thrown upward at a speed of 171 feet per second by a machine from a height of 17 feet off the ground. the height h of the object after t seconds can be found using the equation h = − 16t^2 + 171t + 17 when will the height be 307 feet? when will the object reach the ground?

a.2.11 s or 8.57 s

b.10.79 s

Step-by-step explanation:

We are given that

Initial velocity=171 ft/s

Height  at which the object is thrown=17 ft

The height h of the object after t seconds can be found by the equation

a.We have to find  the time taken by object to reach the  height 307 ft.

Substitute the value

Quadratic formula :

Where

By using quadratic formula

Hence, the object will take 8.57 s or 2.11 s to reach the height 307 ft.

b.We have to find the time taken by object to reach the ground.

When the object reach the ground, then h=0

Substitute the value

Again by using quadratic formula

It is not possible because time cannot be negative.

Hence, the object will take 10.79 s to reach the ground.

answer by yourhope:

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: )

x =-.20752

step-by-step explanation:

4^(x+2)=12

4^(x+2)=12

take the log base 4 on each side

log 4 (4^(x+2) = log 4(12)

we know log b(a^y) = y log b (a)

(x+2) log 4(4) = log 4 (12)

x+2 = log 4 (12)

we know   logb c = loga c/loga b

we want to convert to base 10   so a = 10

by default, we do not write the 10   c = 4   and b = 10

log4 10 = log 12/log 4

log4 10 = log 12/ log 4

x+2 = log 12/ log 4

subtract 2 from each side

x +2 -2 = log 12/ log 4 -2

x = 1.79248125 -2

x =-.20752