X 4. Verify x + (y + z) = (x + y) + z for following values of x, y and z. 2 - 5 5 3 5 -7 -7 (ii) X= 5, y = Z= (X==Z= 6 9 4 6 8 -3 3 - 7 3 6 2 8 (H) X=- y = (iv) X= - ZE 5 10 5 9 10 15 3 1 Z=​