Answer:
( 1, -4)
Step-by-step explanation:
To find this answer you go over 2 to the right on the x-axis, then go down 6 on the y-axis. This gives ( 1, -4).
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:
x=0
Step-by-step explanation:
solve for x by simplifying both sides of the equation, then isolating the variable. which got me x=0
Answer:
4.
or -5 (It's a negative slope)
5. 0 (It's a horizontal line)
6. 
Formula: 
First one is $16 and the second is $276.25