Please help! timed questions

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?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ac=26 and ch=8, find bh.

Will give brainliest b. describe the function over each part of its domain. state whether it is constant, increasing, or decreasing, and state the slope over each part.