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39 votes
39 votes
What is -9 in parenthesis to the 5th power divided by -9 in parenthesis to the 7th power?

User Surreal
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2 Answers

15 votes
15 votes

Answer:

1/9 to the 2nd power or 1/81 (Depends on what the question wants)

Explanation:

Since we are doing (-9^5) ÷ (-9^7). You're going to take those two -9s and keep it as just one -9 because they're the same and we'll need them together anyways. Now you're gonna subtract the original bases' exponents (5 - 7) which is going to get you -2. We did this because of the quotient rule which is an exponent rule that applies to expressions where you divide two numbers with the same base, but different powers / exponents. Now you're left with 9^-2. However, exponents cannot ever be negative so you must make this number's reciprocal by flipping the invisible one below the number and making it a numerator by placing it above the number. Doing so turns the exponent positive (so now it looks like 1 over 9^2 aka 1/9^2) which makes it now a valid answer. If the question wants you to evaluate then you multiply 9 by itself as many times as the exponent says to. In this case that'd get you 1/81. Hope this helped so you can do problems like this one with less trouble.

User Ulix
by
2.6k points
19 votes
19 votes

Answer:

1/81

Explanation:

User Mehmood
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3.2k points