还剩4页未读,继续阅读
文本内容:
第3章 整式的加减
3.4 整式的加减
3.去括号与添括号第1课时 去括号[学生用书P81]1.a-1的相反数为 A.a-1B.a+1C.1-aD.-a-12.下列各式中,去括号正确的是 A.x+2y-1=x+2y-1B.x-2y-1=x+2y+2C.x-2y-1=x-2y-2D.x-2y-1=x-2y+23.化简a+b-2a-b的结果是 A.3b-aB.-a-bC.a+3bD.-a+b4.-[a-b-c]去掉括号后为 A.-a-b-cB.-a-b+cC.a+b-cD.-a+b-c5.[xx·株洲]计算3a-2a-1=__ __.6.在括号前填入正号或负号,使左边与右边相等.1y-x=_ __x-y;2x-y2=__ __y-x2;3x-y3=__ __y-x
3.7.计算x-y+z-x-y-z+x+y-z=__ _.8.先去括号,再合并同类项135a+4-3a-10;28a-4b-4a+4b-c-2a;3-3x2+3x-4x2-2x2-3x+6;47a2b-ab-2a2b-3ab.9.先去括号,再合并同类项1-32s-5+6s;23x-;36a2-4ab-4;4-32x2-xy+4x2+xy-6.10.[xx·甘井子区期末]先化简,再求值2x2-1+3x+41-3x-2x2,其中x=-
1.11.[xx·崆峒区期末]先化简,再求值-a2b+3ab2-a2b-22ab2-a2b,其中a=-1,b=-
2.12.[xx·江津区期末]先化简,再求值2×-[2x2-32xy-x2-2xy],其中x=-2,y=.13.[xx·卢龙县期末]先化简,再求值-6x+33x2-1-9x2-x+3,其中x=-.14.已知2xmy2与-3xyn是同类项,计算m-m2n+3m-4n+2nm2-3n的值.15.[xx·凉州区期末]先化简,后求值-2mn-3m2-[m2-5mn-m2+2mn],其中m、n满足|m-1|+n+22=
0.参考答案【分层作业】1.C2.D3.A4.D5.a+16.- + -7.x+y+z8.解135a+4-3a-10=15a+12-3a+10=15-3a+12+10=12a+22;28a-4b-4a+4b-c-2a=8a-4b-4a-4b+c-2a=8-4-2a+-4-4b+c=2a-8b+c;3-3x2+3x-4x2-2x2-3x+6=-3x2+3x-4x2-2x2+3x-6=-3-4-2x2+3+3x-6=-9x2+6x-6;47a2b-ab-2a2b-3ab=7a2b-7ab-2a2b+6ab=7-2a2b+-7+6ab=5a2b-ab.9.解1-32s-5+6s=-6s+15+6s=15;23x-=3x-=3x-5x+x-4=-x-4;36a2-4ab-4=6a2-4ab-8a2-2ab=-2a2-6ab;4-32x2-xy+4x2+xy-6=-6x2+3xy+4x2+4xy-24=-2x2+7xy-
24.10.解2x2-1+3x+41-3x-2x2,=2x2-1+3x+4-12x-8x2,=-6x2-9x+3,把x=-1代入-6x2-9x+3=-6+9+3=
6.11.解原式=-a2b+3ab2-a2b-4ab2+2a2b=-ab2,当a=-1,b=-2时,原式=--1×-22=
4.12.解原式=-6xy+5x2-2x2-6xy+3x2-2xy=-6xy+5x2-2x2+6xy-3x2+2xy=2xy,当x=-2,y=时,原式=2×-2×=-
2.13.解原式=-6x+9x2-3-9x2+x-3=-5x-
6.当x=-时,原式=-6=-.14.解因为2xmy2与-3xyn是同类项,所以m=1,n=
2. m-m2n+3m-4n+2nm2-3n=m-m2n-3m+4n+2nm2-3n=m-3m+4n-3n+2nm2-m2n=-2m+n+m2n.当m=1,n=2时,原式=-2×1+2+12×2=
2.15.解由|m-1|+n+22=0可知m=1,n=-2,∴原式=-2mn+6m2-m2-5mn+5m2+2mn=-2mn+6m2-m2+5mn-5m2-2mn=mn=-
2.关闭Word文档返回原板块。