When the price of gas is p dollars per gallon, the supply equation is given by , where S is the number of gallons of gas supplied by suppliers. At a price of $2.80 per gallon, 800 gallons of gas are demanded by consumers. If the demand equation is linear and the market price (at which supply and demand are equal) is $3.20 per gallon, find the demand equation in slope-intercept form. (An answer to this part in the proper format is D=-42p 300 You should type the numbers you find without decimal places, commas or spaces and accurate to the nearest integer. Type an uppercase D and a lowercase p)