.1d + .25q = 2.00 solve for q this lets us state quarters in terms of dimes.
.25q = 2 - .1d
q = (2 - .1d)/.25
q = 8 - .4d
d | 0 | 5 | 10 | Dimes have to be in multiples of 5 because we cannot use nickels.
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q | 8 | 6 | 4 | Quarters are in multiples of 2 sue to the dimes.
label the y - axis as q, in multiples of 2, and the x axis as d, in multiples of 5, and now you can graph.