Question

If g(x) =2x-3 and fog (x)=4x -9 ,find f(x)​

Answer 1

To answer this, we need to ask, what did f do to "2x-3" to turn it into 4x-9.

Well, we can multiply 2x-3 by 2 to give us the 4x in 4x-9.

But 2(2x-3) = 4x-6, so we're not quite there. We need to also subtract 3 to turn -6 into -9.

So f(x) = 2x-3 would give (f o g)(x) = 4x-9.

Oh, f(x) = g(x). Weird.