Maria invested $600 in three accounts. The savings account paid 5%, the Mutual fund paid 9% and the CD paid 7%. In one year, Maria earned $40 in interest. If she put three times as much in savings as she put in the CD and twice as much in the mutual fund as she put in the CD, how much money did she put in each account?

36

step-by-step explanation:

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.