Hi Nadiuska,
Since the other posters have already correctly answered the question, I won't rehash any of that work here. Instead, I'll elaborate a bit more on the Exponent rules involved. As a category, you won't see too many Exponent rule prompts on Test Day (probably 2-3, not counting squared-terms or Quadratics).
In this DS prompt, the two Facts test your knowledge of 2 specific exponent rules:
1) What happens when you raise a base to a NEGATIVE exponent.
2) What happens when you raise a base to a 0 exponent.
For the first rule, when raising a base to a NEGATIVE power, you essentially "flip" the calculation and turn the negative into a positive...
\(3^{-2}\) = 1/\(3^{2}\)= 1/9
For the second rule, when an exponent-based calculation = 1, you have a few different possibilities:
1) The base = 1, so the exponent could be anything.
2) The base = -1 and the exponent is an even integer.
3) The exponent is 0, so the base could be anything.
While knowing these rules won't lead to a lot of points on Test Day, they can help you to pick up a couple of additional correct answers. As you string together enough of the rarer question types, you can see a nice bump-up in your score.
GMAT assassins aren't born, they're made,
Rich
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