Question 6. [3+3+2+2 = 10 marks] Given the rings A = A, +, > with A = {a+b2: a,b Q}, and B = B, +, with B = {a+b5: a,b Q}. (a) Prove that the mapping 0: A B defined by 0(a+b2)= a +b5 is not an isomorphism. (b) Show that the trinomial equation x - 2ax + (a-26) = 0 has solutions in ring A for a, b Q. (c) Write down a trinomial equation that has solutions in ring B. (d) Provide a reason why A & B.