Answer:
y=1.25x
Step-by-step explanation:
More information is needed to produce an equation under the conditions in the problem you have. Without that information and with only this information, we can write the following equation or function.
Suri charges per day to walk a dog. We know after 5 days the cost is $6.25 and after 7 days the cost is $8.75. We can find the rate she charges by subtracting the costs and dividing by the difference in days.
Suri charges $1.25 per day.
If y is the cost and x is the number of days, we write y=1.25x. We can input any number of days in for x and find the cost y by multiplying the number by 1.25.