You should tell your mom to bake 8 cupcake batches
Answer: D. 7^11
Reason:
The rule we use is 
When multiplying exponentials of the same base, we add the exponents.
The exponents 5 and 6 add to 5+6 = 11
So,

The base stays the same the entire time.
Plug 7 into each y. 9(7) -4(7) +3
63-28+3
The answer is 38
Hmmm...
We have to divide 12 by 8, since we need to see how 8 students will share 12 slices.
12/8=1 and 1/2
So, each student can have a slice and a half, but since we aren't allowed to cut the slices...
We can let each student have one slice, with 4 left over, so...
Every student can have one slice, and then half can have a second slice :)!
I'm not sure if that is what was meant by the question, but that was all I could think of.
I hope I helped! :)