Arental car agency charges $17 per day plus $.07 per mile to rent a certain car. another agency charges $22 per day plus $.05 per mile to rent the same car. how many miles per day will have to be driven for the cost of a car from the first agency to be greater than the cost of a car from the second agency

Let x represent the number of miles driven. Then the charges from the first agency are ...

... c1 = 17 + 0.07x

and those from the second agency are ...

... c2 = 22 + 0.05x

The first agency's charges will be greater when

... c1 > c2

... 17 + 0.07x > 22 + 0.05x . . . . . . . substitute the above expressions

... 0.02x > 5 . . . . . . . . . . . . . . . . . . . . subtract 17+.05x

... x > 5/0.02

... x > 250

250 miles per day will have to be driven to make the first agency's charges greater.

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18