A rational exponent is a fraction used as an exponent. Its bottom number names the root, and its top number names the power. Rewrite the expression using those two jobs, then use Desmos for a quick check. A matching value at one input isn't proof that two expressions are equivalent for every allowed input.
Hints
- Hint 1
The denominator of a fractional exponent tells you which root to take. For example, a denominator of means a cube root. How does that help you read the root operation in a rational exponent?
- Hint 2
A positive test value can show that two expressions don't match if their results differ. Agreement at one value alone doesn't prove equivalence, though. Which positive value would make a root convenient to evaluate?
Step-by-step
Read the power and root
Step 1Read the denominator
The bottom number means a sixth root: . The condition means this even root is defined.
- Step 2
Get a useful check value
Choose because , so its sixth root is a whole number. Type and in Desmos; it prints . Don't use for this check: every option equals there.
- Step 3
Apply the numerator
The top number says to raise that sixth root to the fifth power: .
- Step 4
Put the power inside the root
Raising the sixth root to the fifth power gives the same result as taking the sixth root of the fifth power: . Add in Desmos; it also prints . That check agrees with the exponent rule, which proves the match for every positive . So the equivalent expression is . Choice B.