Set up a cost equation C(m) where m is the number of miles:

C(m) = Cost per mile * m + Service Fee

Plugging in the service fee of 50 and cost per mile of 1.75, we get:

C(m) = 1.75m + 50

The question asks for what m is C(m) = 71. So we set C(m) = 71 and solve for m:

1.75m + 50 = 71

Solve for

*m*in the equation 1.75m + 50 = 71

**Step 1: Group constants:**

We need to group our constants 50 and 71. To do that, we subtract 50 from both sides

1.75m + 50 - 50 = 71 - 50

**Step 2: Cancel 50 on the left side:**

1.75m = 21

**Step 3: Divide each side of the equation by 1.75**

1.75m/1.75 = 21/1.75

m =

**12**