II. IDENTIFICATION. State the property of mathematical systern shown below. Write your answer before the number.

1. 5 x 1/5 = 1
2. 17 + 2 = 2 + 17
3. a (b + c) = ab + ac
4. -10 + 10 = 0
5. X + (y + z) = (x + y) + z
6. a x 1=a
7. 2n (a + b) = 2an + 2bn
8. 12x + 5y = 5y + 12x
9. 5 (7 x 9) = (5 x 7) 9
10. 10 -1 = -1 x 10​