Answer:
a) 4 - 
b) 1 - 
c) 6 - 
Step-by-step explanation:
It simply asks the steps to go from the original displacement formula to isolate a (the acceleration). It's just a matter of moving items around.
We start with:

We then move the vt part on the left side, then multiply each side by -1 (to get rid of the negative on the at side and to match answer choice #4):

Then we multiply each side by 2 to get rid of the 1/2, answer #1:

Finally, we divide each side by t^2 to isolate a (answer #6):

The answer is B because the x doesn’t repeat in that one.

part B)
the slope is always in a linear equation, the coefficient of the independent variable, in this case namely "35".
35 or 35/1 dollars/day means
for every passing day the car is rented out, the charge is $35, so if you rent the car "d" days, you'll be charged 35d.
No. when the line reaches 4 on the x axis it is at 13 on the y axis.
The car goes 40/3 miles per gallon of gas. 320 miles is 960/3 miles. 960/40 is 24. 24 gallons is your answer.