Answer:
a) The equation which represents Ama-zon's charges is

b) The equation which represents You-tube's charges is

c) Total number of movies which need to be rented should 5 so that both have equal bills.
d) the amount will be $168.95 which would be same for both company after renting 5 movies.
Explanation:
Given:
Flat Rate of Ama-zon = $129
Price of each movie rental = $7.99
Let 'x' represents the number of movie to be rented.
Solving for part a
Hence Total amount charge by Ama-zon will be equal to sum of Flat Rate of Ama-zon and Price of each movie rental multiplied by number of movie to be rented.
Framing in equation form we get;
Total amount charge by Ama-zon =
(let it be equation 1)
Hence the equation which represents Ama-zon's charges is

Also Given:
Flat Rate of You-tube = $144
Price of each movie rental = $4.99
Let 'x' represents the number of movie to be rented.
Solving for part b
Hence Total amount charge by You-tube will be equal to sum of Flat Rate of You-tube and Price of each movie rental multiplied by number of movie to be rented.
Framing in equation form we get;
Total amount charge by You-tube =
(Let this be equation 2)
Hence the equation which represents You-tube's charges is

Solving for part c
To determine number of movies to be rented so that both have equal bills.
i.e we need to find the value of x
Total amount charge by Ama-zon = Total amount charge by You-tube

Hence Total number of movies which need to be rented should 5 so that both have equal bills.
Solving for part d.
Now Substituting the value of x = 5 which makes both the company charge equal we will find the dollar amount.
Total amount charge by Ama-zon =

Total amount charge by You-tube =

Hence the amount will be $168.95 which would be same for both company after renting 5 movies.