(-2007)×(-53 又 51/52)+1678×(-53又51/52)-329×53 又 51/52
=(-2007+1678+329)×(-53 又 51/52)
=0×(-53 又 51/52)
=0
a★b=-a×b-(a+b),
3★4即a=3,b=4
3★4=3×4-(3+4)=5
所以(3★4)★(-5)
=5★(-5)
=5×(-5)-[5+(-5)]
=-25-0
=-25
(-2007)×(-53 又 51/52)+1678×(-53又51/52)-329×53 又 51/52
=(-2007+1678+329)×(-53 又 51/52)
=0×(-53 又 51/52)
=0
a★b=-a×b-(a+b),
3★4即a=3,b=4
3★4=3×4-(3+4)=5
所以(3★4)★(-5)
=5★(-5)
=5×(-5)-[5+(-5)]
=-25-0
=-25