SOLUTION: If f(x) = log3 (x + 1), what is f−1(2)?

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Question 1134309: If f(x) = log3 (x + 1), what is f−1(2)?
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29+=+log%283+%2C%28x+%2B+1%29%29,
what is f%5E-1%282%29
first find inverse f%5E-1%28x%29
replace f%28x%29 with y
y=+log%283+%2C%28x+%2B+1%29%29...swap x and y
x=+log%283+%2C%28y+%2B+1%29%29....solve for y;
apply rule for logarithmic equations, log%28b%2Ca%29=c is equivalent to+b%5Ec=a

in your case b=3,a=y%2B1 and c=x
+3%5Ex=y%2B1
+y=3%5Ex-1
f%5E-1%28x%29=3%5Ex-1
=>
f%5E-1%282%29=3%5E2-1
f%5E-1%282%29=8