Let f (r, y, x) be the real estate tax function of Exercise 13.

(a) Determine the real estate tax on a property valued at $100,000 with a homeowner’s exemption of $5000, assuming a tax rate of $2.20 per hundred dollars of net assessed value.

(b) Determine the real estate tax when the market value rises 20% to $120,000. Assume the same homeowner’s exemption and a tax rate of $2.20 per hundred dollars of net assessed value. Does the tax due also increase by 20%?