If the functions are defined as fx=x and gx=1-x, then what is the common  domain of the following functions: f+g,f-g,fg,gf,g-f

The given functions are fx=x, gx=1-x The domain of the functions and both not equal to zero when x>0,1-x>0 ⇒ x>0, x-1<0 Therefore, the common domain to all functions required is 0