Answer:
y = 0.5x + 3.5
Explanation:
The y- intercept (boarding fee) is what the price is starting as. It basically is saying that once you sit in that cab, you are paying $3.50. Then, per mile, you have to pay 50 cents added onto that $3.50. So, your slope is the 50 cents.
I don't really know if that explantation made sense but I'm almost positive my answer is right.