linear function

Question

the owner of a grocery store finds that she sell 980 gallons of milk each week at $2.69 per gallon and 1220 gallons of milk each week at $2.49 per gallon.

Find a linear function G(p) that gives the number of gallons sold as a function of

the price of milk

Answer 1

G(p)=ap+b is the general form of the linear equation.

a is the slope=(1220-980)/(2.49-2.69)=240/(-0.2)=-1200.

Point-slope form, G(p)=-1200(p-2.49)+1220=-1200p+2988+1220=4208-1200p.

So G(p)=4208-1200p.