So far i've proved that Ann(a) is a subring (under addition and multiplication), now to prove it's an ideal i've shown;
say a1, a2 elements of R, then a1 - a2 element of R, now i need to show rK, Kr to be an element of R...how do I go about this?
So far i've proved that Ann(a) is a subring (under addition and multiplication), now to prove it's an ideal i've shown;
say a1, a2 elements of R, then a1 - a2 element of R, now i need to show rK, Kr to be an element of R...how do I go about this?