Ok, so there is a half gallon and a gallon of milk, which one should I buy, if I wanted the cheaper one? The half is $1.56 and the gallon is $3.09.
Do you need help ma'am?
Yes, which would be cheaper for me to buy? Half Gallon or Full Gallon?
Oh um, I am not sure. Sir, can you do the math on which is cheaper?
Yes, hold on a minute.
.... so y=1.44/2x+.21? Finally, got it!
So, you need to subtract 3.09 from 1.65, and 4 from 2. Then you will have a fraction as -1.44/-2 and if you simplified that fraction it would be 1.44/2. Your slope is 1.44/2. Then to find your y-intercept you need to multiply 1.44/2 *4. Which is 2.88, then subtract 2.88 by 3.09. Which is .21, and that is your y-intercept. To figure out which milk you should buy, use the equation y=1.44/2x+.21