Answer: <u>3 hours and 20 minutes</u>
Step-by-step explanation:
3x + 2(3)x = 30
3x + 6x = 30
9x = 30
9/9 = 30/9
x = 3 1/3 hours
The expression which relates the total time taken and the time taken for the trip is [15s + 15(s+2)] / s² + 2s and 2.32 hours respectively.
<em>Travel time = distance ÷ speed </em>
<u>Second half of the trip</u> :
- <em>Distance covered = 15 miles</em>
<u>Time taken for second half of trip</u> :
Time taken = 15 / s
<u>First half of the trip</u> :
- <em>Speed = s + 2 mph </em>
<u>Time taken for first half of trip :</u>
Time taken = 15 / (s+2)
<u>Total time taken :</u>
<em>First half + second half</em>
15/(s+2) + 15/s = [15s + 15(s+2)] / s² + 2s
B)
If s = 12
<em>Substitute s = 12 into the expression</em> :
[15(12) + 15(12+2)] / 12² + 2(12)
[180 + 210] / 144 + 24
390 / 168
= 2.32 hours
Therefore, the total time taken is 2.32 hours.
Learn more : brainly.com/question/18796573
We have

and

so the equation is indeed exact. So we want to find a function
such that


Integrating both sides of the first equation wrt
gives

Differentiating both sides wrt
gives

So we have

or

Answer:
d
Step-by-step explanation: