No, if you are taking f(x)= log(x), y= 5 log(x- 1) is NOT "y= 5f(x)". It is, rather, y= 5 f(x- 1). Generally speaking changes inside the "parent" function are changes to x and reflect horizontal changes to the graph. For example, f(1)= log(1)= 0 so that f(2)= log(2-1)= 0 so that, in effect, the graph is shifted one place to the right. Changes outside the parent function are changes to y, vertical changes. Multiplying by 5 stretches the graph vertically by a multiplier of 5.