Given:
y is the amount of change from a $10 bill.
x is the number of bagels bought
Given coordinate is (4,7). Bought 4 bagels and had a change of $7.
10 - 7 = 3 cost of the bagels
3 / 4 = 0.75 cost of each bagel.
The function should be:
f(x) = -0.75x + 10
Where 0.75 is the cost per bagel bought, x is the number of bagels bought, $10 is the cash paid for the bagels and f(x) is the amount of change received from the purchase of bagels.
