帮解答几道prep数学题

mauricew

146.    14746-!-item-!-187;#058&010097

If the symbol △ represents either addition or multiplication, which operation does it represent?

(1)  a △ b = b △ a for all numbers a and b.

(2)  a △ ( b – c ) = ( a △ b ) – ( a △ c )for all numbers a, b, and c.

Answer: B

[此贴子已经被作者于2008-6-25 22:03:00编辑过]