math-destroyer

Question is: If f is a function where f(x-1) = x+1 for all real numbers, find the expression for f(1-x) Answer: if f(x-1) = x+1, then the function f(x) = x+2, from which the value is obtained for f(x-1) = 1-x+2 = 3-x In this problem what is giving me trouble is that i'm not entirely sure...