this is trying to teach you about the slope intercept problem
okay so what you wanna do is first gather up your information about the problem, which was that they bought 7 sodas
so...
.5*7= 3.5
28.5-3.5= 25
so your equation would be:
25= 1.25x+2.50y
and when you want to graph it
you want to use the formula for the slope intercept which would be y=mx+b
2.5y= 1.25x+25
so
y=-0.5x+10
and then youre just gonna locate the y intercept on your graph, so youre gonna have to plot it on 10 on the y axis
and then from there since our slope was 1/2 you want to go down one and to the right by 2 because it is your rise/run so your rise would be 1 and your run would be 2. and yeah! that's how you graph it p much.
hope this helped you!!