The volume of a box(v) varies directly with its length(l). if one of the boxes has a volume of 288 cubic inches and a length of 12 inches, what is the constant of proportionality for the group of boxes?

24

Step-by-step explanation:

Varies directly means that something constant times l equals V or V=kl where k is that constant.  

Plug in point given 288=k(12) and solve the constant of proportionality by dividing both sides by 12.

k=288/12=24

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.