Help read the screenshot and answer please.

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Mr.walker is looking at the fundraiser totals for the last five years , how does the mean of the totals compare to the median?

Robin spent 25% more time on his research project than he had planned he’s been an extra h ours on the project which of the following expressions could represent the number of hours rob actually spent on the project