Final answer:
The expression 2x2x2, which represents the number of coins on the third day, can also be written using exponents as 2^3 or 8^1.
Step-by-step explanation:
The number of coins on the third day is represented as 2x2x2, which is actually the same as 2 cubed (since cubing a number means multiplying the number by itself three times). In mathematics, when we want to use exponents to express repeated multiplication, we can write 2x2x2 as 23. Another expression using exponents that is equivalent to this is 81 because 2 cubed equals 8, and any number to the power of one is itself.