2. Number pairs (4, 5) and (5, 4) indicate the same position. (error)

3.5/8a < a (a > 0) pair

4.Y = 1/2 (x ≠ 0), and x is directly proportional to y. (error)

5. Two triangles with the same area can definitely form a parallelogram. (error)

6. The second hand on the clock is moving. (error)

7. A commodity is sold at a 10% discount, which is cheaper than the original price 17%. (right)

8. The sides of cylinders and cones are curved. (right)