I am sticking with my first answer - I think that the algebra is correct
My original graph had the wrong coefficients so it was incorrect ***
This graph is correct and it shows that there are no values for $$f^{-1}(6)$$
https://www.desmos.com/calculator/d86qhh4t5m
So I still say there are no solutions. Because x=6 is not in the domain of the invese function !
What answer did Alan get?
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Also Chris the whole graph is of no consequence because there are restrictions on the range of the inverse fuction,
y>3 therefore x<0 therefore $$f^{-1}(6)$$ does not exist.
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