8. why should you write most sentences in the active voice?
a. it is important to emphasize the receiver of the action in the active voice.
b. the active voice makes a sentence more interesting and lively.
c. the active voice is always in the present tense.
d. who or what performed the action is not named in the sentence in the active voice.

The correct answer is  

C) The active voice makes a sentence more interesting and lively.

Explanation:

in the problem you wrote said that the taxi charges $0.070 per mile(which would be 7 cents per mile), but then in your suggested equation you have it as $0.70 per mile (which is 70 cents per mile).

the latter seems more realistic, so i will assume that the taxi costs $5.00 and charges $0.70 per mile with tolls costing an additional $3.50. and it asks you to find how far you can travel on $36.50.

let x the number of miles traveled. since the taxi charges $0.70 per mile, multiplying this by the miles traveled (x) will yield the cost of the taxi ride as far as how far it took you. then adding this amount to the cost of the taxi ($5.00) and the additional cost for the tolls ($3.50) will give you the total cost of the taxi ride ($36.50)

that is,

            (0.70)x + 5.00 + 3.50 = 36.50

adding the like terms on the left-hand side of this equation, we arrive at the following:

            (0.70)x + 8.50 = 36.50

subtracting 8.50 from both sides of the equation, we get:

            (0.70)x = 28.00

to solve for x, divide both sides of the equation above by the coefficient of x (that being, 0.70):

            x = 40

thus, you can travel up to 40 miles on $36.50