Answer:
8^12
Explanation:
Exponents are confusing at first. You subtract them when dividing, and add them when multiplying, if the base number is the same.
Picture 8 to the 15th as a numerator of:
8x8x8x8x8x8x8x8x8x8x8x8x8x8x8 over a denominator of
8x8x8
To solve that, you'd cancel out 3 of the top 8s and the three bottom 8s, marked in bold to be easier to see. This leaves you with
8^12
Does that help?
Happy to answer questions.