Answer: 5^(-18)
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Step-by-step explanation:
The rule we use is
a^b * a^c = a^(b + c)
This says that if we multiply exponential expressions with the same base, then we add the exponents. We keep the base the same the entire time.
For example, 2^3*2^4 = 2^(3+4) = 2^7
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For this problem, we'll say,
5^(56)*5^(22)*5^(-96)
5^( 56+22+(-96) )
5^(-18)
Be sure that you use parenthesis so that you tell your teacher that all of the -18 is in the exponent. Saying 5^-18 could lead to ambiguity.