第7课时 去括号(1)
1.下列各式中,与a-b-c的值不相等的是 ( )
A.a-(b+c) B.a-(b-c)
C.(a-b)+(-c) D.(-c)+(-b+a)
2.化简-[0-(2p-q)]的结果是 ( )
A.-2p-q B.-2p+q C.2p-q D.2p+q
3.下列去括号中,正确的是 ( )
A.a-(2b-3c)=a-2b-3c
B.x3-(3x2+2x-1)=x3-3x2-2x-1
C.2y2+(-2y+1)=2y2-2y+1
D.-(2x-y)-(-x2+y2)=-2x+y+x2+y2
4.去括号:
a+(b-c)= ; (a-b)+(-c-d)= ;
-(a-b)-(-c-d)= ;
5x3-[3x2-(x-1)]= .
5.判断题.
(1)x-(y-z)=x-y-z ( )
(2)-(x-y+z)=-x+y-z ( )
(3)x-2(y-z)=x-2y+z ( )
(4)-(a-b)+(-c-d)=-a+b+c+d ( )
6.去括号:
-(2m-3); n-3(4-2m);
16a-8(3b+4c); -(x+y)+(p+q);
-8(3a-2ab+4); 4(rn+p)-7(n-2q).
7.先去括号,再合并同类项:
-2n-(3n-1); a-(5a-3b)+(2b-a);
-3(2s-5)+6s; 1-(2a-1)-(3a+3);
3(-ab+2a)-(3a-b); 14(abc-2a)+3(6a-2abc).
8.把-︱-[ a-(b-c)]︱去括号后的结果应为 ( )
A.a+b+c B.a-b+c C.-a+b-c D.a-b-c
9.化简(3-)-︱-3︱的结果为