I need help please solving

What is the common difference in the following arithmetic sequence 7,3,-1,-5

Which table shows a proportional relationship between miles traveled and gas used?

The table below shows the approximate height of an object x seconds after the object was dropped. the function h(x)= -16x^2 +100 models the data in the table. for which value of x would this model make it the least sense to use? a. -2.75 b. 0.25 c. 1.75 d. 2.25