Question

F(g(x))=x+1 และ f(x)=x-1 หาg(x)

Answer 1

Let's do this:  start with f(x) = x -1.  Now substitute the label "g(x)" for x:

f(g(x)) = g(x) - 1     and we are told that f(g(x)) equals x + 1.  

Thus,                     g(x) - 1 = x + 1

Adding 1 to both sides, we get 

                              g(x) = x + 2               (answer)