Suppose that a, b, c are integers between 0 and 999 inclusive, and let their decimal representations be a = a1a2a3, b = b1b2b3, c = c1c2c3. For example, if a = 56, then a1 = 0, a2 = 5, and a3 = 6. Assume that 7 divides a, b, and c. (i) By performing suitable row operations, show that 7 divides the determinant a1 b1 c1 a2 b2 c2 . a3 b3 c3?