Piece-wise defined function

been having trouble :,)

The gades foundation and hbm corporation are eager to donate generously to their favorite charities. the gades foundation donated $250 in the first month, and each month afterward their cumulative donation total increases by 100$ the hbm corporation donated $64, in the first month, and each month afterward their cumulative donation total increases by 75%. in which month will the hbm corporation's cumulative donation total first exceed the gades foundations' cumulative donation total?

(98 points) i need with 5 questions. answer definitions are welcomed, but not necessary.

Simplify the expression. -2/5(10+15m-20n)