9514 1404 393
Answer:
-7
Step-by-step explanation:
It is helpful to recognize 128 = 2^7. Then you know ...
[tex]\log_2\dfrac{1}{128}=\log_2{2^{-7}} =\boxed{-7}[/tex]
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If you don't know that, you can use the change of base formula:
[tex]\log_2{\dfrac{1}{128}}=\dfrac{\log{\dfrac{1}{128}}}{\log{2}}=\dfrac{-2.1072}{0.30103}=\boxed{-7}[/tex]
