Question

A student states that the constant of proportionality is 2.5 since 10 - 7.5 = 2.5.

Answer 1

I cannot see the table. But if I could that would be helpful.

But, if you were to look at the table see if the numbers are increasing or decreasing for the y column. Once you figure this out, find out how much the numbers are increasing/decreasing by and that should be the answer for the constant of proportionality. If it is decreasing, it would be a negative number. If it is increasing, it would be a positive number.