You need to start by multiplying $23.95 by four to get the b value. You get $95.8, which is the cost for only the car for 4 days. The 0.32 is the m (growth rate) and the 150 is the y (the total number)
Here is your equation:
150=0.32x+95.8 Remove alike terms.
-95.8 -95.8
54.2=0.32x Divide by the number in front of the variable
------- -------
.32 .32
x=169.375 miles
