Write the expression using a single exponent.

8. Start Fraction 2 superscript 8 baseline over 2 superscript 7 baseline End Fraction (1 point)
21
2 superscript eight-sevenths baseline
256
215

2 superscript one-seventh baseline

The expression "Start Fraction 2 superscript 8 baseline over 2 superscript 7 baseline End Fraction" can be simplified to 2 superscript eight-sevenths baseline.

To write the expression using a single exponent, we need to simplify the fraction in the exponent to a single exponent.

The given expression is:
Start Fraction 2 superscript 8 baseline over 2 superscript 7 baseline End Fraction

To simplify this, we subtract the exponents in the denominator from the exponent in the numerator. In this case, we have 8 - 7 = 1.

Therefore, the expression using a single exponent is:
2 superscript 1 baseline

Simplifying the exponent 2^1, we get:
2

So, the correct answer is 2.