1.设这个整式是X
则X+(2ab-3b+3ab+4)=5bc-3ac+2ab+a
所以X=(5bc-3ac+2ab+a)-(2ab-3b+3ab+4)
正确答案是X-(2ab-3b+3ab+4)
=(5bc-3ac+2ab+a)-2(2ab-3b+3ab+4)
=5bc-3ac+2ab+a-4ab+6b-6ab-8
=5bc-3ac-8ab+a+6b-8
2.a-2=0,b+1=,c=0
a=2,b=-1,c=0
a²-2ab-5a²+12ac+3ab-c²-8ac-2a²
=-6a²+ab+4ac-c²
=-24-2+0-0
=-26