(4,3),(3.3),(4,-1),(4,8) function or not funtion?
(d,7),( d,-7),(d,-1),(k,6) function or not funtion?
(-1,-8),(-8,-2),(-3,-8),(-2,-2)function or not funtion?
( 2, S), ( 6, S), ( -4,S),(-2,N)function or not funtion?