Constants: -5x
like terms: 7, 1
terms: 1, 7, -5x
coeffcients: 5
Using a calculator, you can find out that

and so that means

so your answer is
121 is big enough to assume normality and not worry about the t distribution. By the 68-95-99.7 rule a 95% confidence interval includes plus or minus two standard deviations. So 95% of the cars will be in the mph range

The question is a bit vague, but it seems we're being asked for the 95% confidence interval on the average of 121 cars. The 121 is a hint of course.
The standard deviation of the average is in general the standard deviation of the individual samples divided by the square root of n:

So repeating our experiment of taking the average 121 cars over and over, we expect 95% of the averages to be in the mph range

That's probably the answer they're looking for.
Answer:
<u>u ≤ -6</u>
Step-by-step explanation:
Given :
Add 2 on both sides :
- 22 + 2 ≤ -4u - 2 + 2
- -4u ≥ 24
Divide both sides by -4 (remember the sign changes direction when divided by a negative number) :
- -4u/-4 ≥ 24/-4
- <u>u ≤ -6</u>
Answer: 0.356, 3.65, 35.6, 35.63, 356.06, 356.6
Step-by-step explanation: