I need help with this question, thanks!

1. We have seen that for any commutative ring R, we can make sense of the polynomial ring R[:n]. In particular, if we take R = QLy] (we need to use another variable name here], we can make the polynomial ring R[:t:] = Q[y][:n]. In fact, we just get the poiynomioi ring in two varieties over 11!, denoted by (like, y], with just the arithmetic you expect. [a] Characterize the elements in the idea] (any) C Q[:v,y] in terms of the values they take] when we substitute (my) = (U, 0). (b) Show that the ideal (3:, y} is not a principal ideal