How do you find the inverse of f(x)=(7/x)-3f(x)=(7x)3?

1 Answer
Feb 1, 2016

f^-1(x)=7/(x+3f1(x)=7x+3

Explanation:

Given that f(x)=7/x-3f(x)=7x3
We know that if f(x)=yf(x)=y then f^-1(y)=xf1(y)=x

So, from the main equation, by rearranging we get
y=7/x-3\impliesy+3=7/x\implies(y+3)/7=1/xy=7x3y+3=7xy+37=1x
:.x=7/(y+3)

We know what x is, so now you know why the answer above is right. (Just replace y to x)