short question from rings and fields subject.please solve question 1 & 3

1. Check whether or not the function f: Z - M3(R) defined by f(n) = n is a ring homomorphism. If it is ring homomorphism then find ker f and img f. 2. Give some examples of a ring homomorphism which is One - one but not onto. ii. Onto but not one - one. iii. Both one - one nor onto. iv. Neither one - one nor onto. 3. In the above Q).No. 1 if A = 4Z = (0, 14, +8, +12, ...}, then find f(A)