(a-3)的4次方+|a+b+9|=0
所以
a-3=0
a+b+9=0
解得a=3
b=-12
3a²b-【2a²b-2ab+a²b-4a²】-ab
=3a²b-3a²b+2ab+4a²-ab
=4a²+ab
=36-36
=0