Find the slope of (0,1) and (2,7)

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?

Sally deposited money into a savings account paying 4% simple interest per year. the first year, she earn $75 in interest. how much interest will she earn during the following year?

What is the area of the shaded sector?