That answer is correct, 9x + 4 -5y. Only like terms are the x terms and we add 3 and 6 together.
Fyi I didn't find this on google or anything I did the calculation on my computer and yes this is correct...
If it's wrong I'm sorry...
Answer:
For the shape you must do 3*3*3 + 2*2*2 + 1 unit cubed, or 36 units^3
For Jessy's jewelry box, you must multiply the side lengths, 3*10*3, or 90 inches^3