Not too sure what you're asking, but...
3(x+2) is the expression
Answer:
744 cubic inches
Step-by-step explanation:
Volume of Styrofoam= volume of big box -volume of glass box
=(10*10*15)-(9*7*12)
=1500-756
=744 cubic inches
I'm assuming the question looks like this?

If so then the answer should be:

Hope this helps!
The asnwer is 32 :) hope it helps