If there are 30 boys and 50 girls in a room, fill out all of the possible ratios of boys to girls that could be made. They already used 30:50 as an example.

3:5

60:100

90:150

120:200

15:25

150:250

180:300

210:350

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.