How do I solve this?

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?

Which is the equation of a line perpendicular to the line with the equation 3x+4y=8

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)