4. Suppose x + y = 2, and y is odd. (i). Prove that r is even, so z is odd. (ii). Prove that (iii). Prove that 3m, n such that 2+y 2 Hint: Use (ii) and the result of Problem 3. (vi). Conclude that I m, 2 = (x, y, z) = 1 = 1. 229= z+yz-y 2 2 x = 2mn, y=m-n, 2=m + n.