Question 668382
Find the inverse of f(x)=2^x.  Here is where I went with this.  Change f(x) to y so it would read y=2^x.  Interchange the y and x to get x=2^y. 
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x=2^y
ln(x) = y*ln(2)
y = ln(x)/ln(2)
Or {{{y = log(2,x)}}}