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How to express exponential equation, 3^c = 27 , as a logarithmic equation

2 Answers

7 votes


log_(3)27 = c

using the law of logs :
log_(b) x = n ⇔ x =
b^(n)

given
3^(c) = 27 then


log_(3) 27 = c


User Akajack
by
7.6k points
6 votes

If you consider the logarithm base 3 of both sides, you have


\log_3(3^c) = \log_3(27)

You can use a rule of logarithms that allow you to turn exponents into multiplicative factors:


\log_a(b^c) = c\log_a(b)

So the equation becomes


c\log_3(3)=\log_3(27)

Now, by definition, you have


\log_a(b)=c \iff a^c=b

So, you have


\log_3(3)=x \iff 3^x=3 \iff x = 1,\quad \log_3(27)=y \iff 3^y=27\iff y=3

So, the equation becomes


1\cdot c = 3 \iff c=3

User Thewisegod
by
7.0k points