Suppose that the functions r and s are defined for all real numbers x as follows. r (x) =3x-4 s (x) =x+4 Write the expressions for (s - r) (x) and (s-r) (x) and evaluate (s +r) ( 1). (s-7) (x) - 1 ( s - r ) ( x ) - [ X ( s + 7 ) ( -1 ) - 0