A FRIEND GAVE MS.MORRIS A GIFT CARD FOR A LOCAL CAR WASH. THE TABLE SHOWS THE LINEAR RELATIONSHIP OF HOW THE VUALE LEFT ON THE CARD RELATES TO THE NUMBER OF CAR WASHES

The table is: Number of washes denoted by x: 0, 8, 12 Amount left on card denoted by y: 30, 18, 12   a.       Write an equation that shows the amount of dollars left on the card Solution: 18 – 30 divided by 8 – 0 = -12/8 On simplest form is -3/2   The equation is y = -3/2x + 30   b.      Explain the meaning of the negative slope above. As the number of car washes increase, the dollars left on the card decreases.   c.       What is the maximum value of x? 0 = -3/2x + 30 2/3 x 3/2 x = 30/1 x 2/3 Cancel 2/3 x 3/2 and reduce 30 by 3 we get 10, 10 x 2 x = 20