ข้อที่ 1.
ข้อใดไม่ถูกต้อง
1
[(-5)+1]×(-2) = [(-5)×(-2)]+[1×(-2)]
2
[(-5)+(-2)]×1 = 1×[(-2)+(-5)]
3
[1×(-5)]+(-2) = (-2)+[(-5)×1]
4
[(-2)×1]+(-5) = (-2)×[1+(-5)]