Why might someone choose to use the y-intercept and the slope to graph a line?

Because if you know where the line crosses the y axis (the y intercept) you can plot a point there. Then with slope you can count to your next plotted point. With the 2 points you can now draw your line.

Answer for 2: his profit would be $2.88 explanation: you have to first multiply 72 and 0.12 together to get $8.64 once you do that you know how much money the shopkeeper made from selling the candy bars individually. so you have to do 8.64-5.76=2.88 hope that ; )answer for 3: yeah i’m sorry i have no idea what number 3 is. i’m sorry i couldn’t with that.