Which linear system of equations does the matrix represent 4 -7 -14 4 -12 4

The john deere company has found that revenue, in dollars, from sales of heavy-duty tractors is a function of the unit price p, in dollars, that it charges. if therevenue r is r(p)= -1/2p^2 +1900pa)how much revenue will the company generate if they sell 700 tractors? b) how many tractors does the company want to sell to maximize the revenue?