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PLZ HELP
Pre-calculus

PLZ HELP Pre-calculus-example-1

2 Answers

6 votes

Answer:

3/4 goes with
\log_2(8^(1)/(4))

-4 goes with
\log_3((1)/(81))

-6 goes with
-3\log_5(25)

1/3 goes with
\log_6(6^(1)/(3))

Explanation:


\log_6(6^(1)/(3))=(1)/(3)\log_6(6)=(1)/(3)\cdot 1=(1)/(3)


\log_2(64)=6 \text{ since } 2^6=64


-3\log_5(25)=-3(2)=-6 \text{ since } 5^2=25


\log_2(8^(1)/(4))=(1)/(4)\log_2(8)=(1)/(4)\log_2(2^3)=(1)/(4)\cdot (3)\log_2(2)=(1)/(4) \cdot 3 \cdot 1=(3)/(4)


\log_3((1)/(81))=\log_3((1)/(3^4))=\log_3(3^(-4))=-4\log_3(3)=-4(1)=-4

Here are few rules I used:


\log_a(b)=x \text{ means } a^x=b


\log_a(a)=1


\log_a(b^r)=r \log_a(b)

User BreyndotEchse
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\bf \textit{Logarithm Cancellation Rules} \\\\ log_a a^x = x\qquad \qquad a^(log_a x)=x \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \log_6(\sqrt[3]{6})\implies \log_6(6^{(1)/(3)})\implies \cfrac{1}{3} \\\\[-0.35em] ~\dotfill\\\\ \log_2(64)\implies \log_2(2^6)\implies 6 \\\\[-0.35em] ~\dotfill\\\\ -3\log_5(25)\implies -3\log_5(5^2)\implies -3(2)\implies -6 \\\\[-0.35em] ~\dotfill


\bf \log_2(\sqrt[4]{8})\implies \log_2(\sqrt[4]{2^3})\implies \log_2(2^{(3)/(4)})\implies \cfrac{3}{4} \\\\[-0.35em] ~\dotfill\\\\ \log_3\left( (1)/(81) \right)\implies \log_3\left( (1)/(3^4) \right)\implies \log_3(3^(-4))\implies -4

User Chris Kooken
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5.1k points