Carl and lisa are renting moving trucks from same company. they pay a fee of x dollars just to rent the truck, and y dollars per mile they drive, carl drives 150 miles and pays $215 lisa drives 120 miles and pays $176 dollars. find the amount of the original fee and cost per miles.

First you have to make equations for Carl and Lisa
x + 150y = 215
x + 120y = 176
Now you can solve by substitution or elimination, I'm going to use elimination, so I'm going to multiply the bottom equation by negative one and solve
x + 150y = 215
-x -120y = - 176
30y = 39
y = 1.3
So it cost $1.30 per mile
Now plug the number into one of the original equations to get x
x + 150 (1.3) = 215
x + 195 = 215
x = 20
So the fee for renting the truck is $20