2.	Mac Renovations has been using the home's interior square feet for his exterior paint cost estimations.
	It was brought to his attention that adding a home's external openings might also be useful in
	predicting the painting cost estimations.
	The following data was gathered from the last 12 houses he had painted.

House	Costs	Square Feet	Openings
1	$ 2,810	2,500	7
2	$ 3,742	3,150	12
3	$ 3,100	2,800	8
4	$ 3,150	2,850	8
5	$ 4,700	4,750	16
6	$ 3,225	2,950	8
7	$ 2,920	2,700	7
8	$ 2,836	2,550	6
9	$ 3,242	2,600	7
10	$ 4,112	3,700	13
11	$ 3,210	2,650	7
12	$ 3,965	3,550	12

Based upon the above data, compute the profit equation that will produce the most accurate painting cost estimates.