21 -6 - NO a) D : {all real numbers}, R: {all real numbers Ob) D: {all real numbers), R; {y >0} O c) D: all real numbers), R: {y < 0} O d) D: {x>0}, R: {all real numbers

21 6 NO a D all real numbers R all real numbers Ob D all real numbers R y gt0 O c D all real numbers R y lt 0 O d D xgt0 R all real numbers class=