Can someone tell me a good definition for “Annuity” please?

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?

Just tell me how to set up the equation.

Atriangle has side lengths of x, x+11, and 3x+5. what is the perimeter? question 1 options: 3x2+38x+55 3x3+38x2+55x 5x+16 4x+16