Cost of Laying Cable. S represents the position of a power relay station located on a straight coastal highway, and M shows the location of a marine biology experimental station on a nearby island. A cable is to laid connecting the relay station at S with the experimental station at M via the point Q that lines on the xaxis between O and S. If the cost of running the cable on land is $3 per running foot and the cost of running cable under water is $5 per running foot, find an expression in terms of x that gives the total of laying the cable. Use this expression to find the total cost when x=1500 and when x =2500.
y (feet)
M (0,3000)

__________ _______>x (feet)
0  Q(x,0) S(10,000,0)