合并同类项计算题

1、合并同类项计算题1a-(a-3b+4c)+3(-c+2b)2 .(3x2-2xy+7)-(-4x2+5xy+6)33ab-4ab+8ab-7ab+ab=_47x-(5x-5y)-y=_523a3bc2-15ab2c+8abc-24a3bc2-8abc=_6-7x2+6x+13x2-4x-5x2=_72y+(-2y+5)-(3y+2)_11(2x2-3xy+4y2)+(x2+2xy-3y2)=_122a-(3a-2b+2)+(3a-4b-1)=_13-6x2-7x2+15x2-2x2_142x-(x+3y)-(-x-y)-(x-y)_162x+2y-3x-2(x-y)=_175-(1-x)-1-

2、(x-1)=_18( )+(4xy+7x2-y2)=10x2-xy19(4xy2-2x2y)-( )=x3-2x2y+4xy2+y321A=x3-2x2+x-4，B=2x3-5x+3，计算A+B=_22A=x3-2x2+x-4，B=2x3-5x+3，计算A-B=_23假设a=-0.2，b=0.5，代数式-(|a2b|-|ab2|)的值为_25一个多项式减去3m4-m3-2m+5得-2m4-3m3-2m2-1，那么这个多项式等于_26-(2x2-y2)-2y2-(x2+2xy)=_27假设-3a3b2与5ax-1by+2是同类项，那么x=_，y=_28(-y+6+3y4-y3)-(2y2-3y3

3、+y4-7)_29化简代数式4x2-7x2-5x-3(1-2x+x2)的结果是_302a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( )313a-(2a-3b)+3(a-2b)-b=_32化简代数式x-y-2x-(x+y)等于_335a2+( )a-7+( )a2-4a+( )=a2+2a+1343x-y-(2x+y)=_35化简|1-x+y|-|x-y|(其中x0，y0)等于_36xy，x+y-|x-y|=_37x0，y0，化简|x+y|-|5-x-y|=_384a2n-an-(3an-2a2n)_39假设一个多项式加上-3x2y+2x2-3xy-4得2x2y+3xy2-

4、x2+2xy，那么这个多项式为_40-5xm-xm-(-7xm)+(-3xm)=_41当a=-1，b=-2时，a-(b-c)-b-(-c-a)_43当a=-1，b=1，c=-1时，-b-2(-5a)-(-3b+5c)_44-2(3x+z)-(-6x)+(-5y+3z)=_45-5an-an+1-(-7an+1)+(-3an)_463a-(2a-4b-6c)+3(-2c+2b)=_489a2+7a2-2a-(-a2+3a)=_50当2y-x=5时，5(x-2y)2-3(-x+2y)-100=_ (三)化简70(4x2-8x+5)-(x3+3x2-6x+2)72(0.3x3-x2y+xy2-y3)

5、-(-0.5x3-x2y+0.3xy2)73-2a2b-3abc-(4ab2-a2b)74(5a2b+3a2b2-ab2)-(-2ab2+3a2b2+a2b)75(x2-2y2-z2)-(-y2+3x2-z2)+(5x2-y2+2z2)76(3a6-a4+2a5-4a3-1)-(2-a+a3-a5-a4)77(4a-2b-c)-5a-8b-2c-(a+b)78(2m-3n)-(3m-2n)+(5n+m)79(3a2-4ab-5b2)-(2b2-5a2+2ab)-(-6ab)80xy-(2xy-3z)+(3xy-4z)81(-3x3+2x2-5x+1)-(5-6x-x2+x3)833x-(2x-

6、4y-6x)+3(-2z+2y)84(-x2+4+3x4-x3)-(x2+2x-x4-5)85假设A=5a2-2ab+3b2，B=-2b2+3ab-a2，计算A+B86A=3a2-5a-12，B=2a2+3a-4，求2(A-B)872m-3n+-4m-(3m-n)885m2n+(-2m2n)+2mn2-(+m2n)894(x-y+z)-2(x+y-z)-3(-x-y-z)902(x2-2xy+y2-3)+(-x2+y2)-(x2+2xy+y2)922(a2-ab-b2)-3(4a-2b)+2(7a2-4ab+b2)944x-2(x-3)-3x-3(4-2x)+8(四)将以下各式先化简，再求值9

7、7a+b=2，a-b=-1，求3(a+b)2(a-b)2-5(a+b)2×(a-b)2的值98A=a2+2b2-3c2，B=-b2-2c2+3a2，C=c2+2a2-3b2，求(A-B)+C99求(3x2y-2xy2)-(xy2-2x2y)，其中x=-1，y=2101|x+1|+(y-2)2=0，求代数式5(2x-y)-3(x-4y)的值106当P=a2+2ab+b2，Q=a2-2ab-b2时，求P-Q-2P-(P-Q)107求2x2-3x+5+4x2-(3x2-x-1)的值，其中x=-3110当x=-2，y=-1，z=3时，求5xyz-2x2y-3xyz-(4xy2-x2y)的值1

8、13A=x3-5x2，B=x2-6x+3，求A-3(-2B)(五)综合练习115去括号：-(a+b)-(a-b)116去括号：-(-x)-y-+(-y)-(+x)117A=x3+6x-9，B=-x3-2x2+4x-6，计算2A-3B，并把结果放在前面带“-号的括号内118计算下式，并把结果放在前面带“-号的括号内：(-7y2)+(-4y)-(-y2)-(+5y)+(-8y2)+(+3y)123合并同类项：7x-1.3z-4.7-3.2x-y+2.1z+5-0.1y124合并同类项：5m2n+5mn2-mn+3m2n-6mn2-8mn126去括号，合并同类项：(1)(m+1)-(-n+m)；(2

9、)4m-5m-(2m-1)127化简：2x2-3x-4x2-(3x2-x)+(x-x2)128化简：-(7x-y-2z)-4x-(x-y-z)-3x+z-x129计算：(+3a)+(-5a)+(-7a)+(-31a)-(+4a)-(-8a)130化简：a3-(a2-a)+(a2-a+1)-(1-a4+a3)131将x2-8x+2x3-13x2-2x-2x3+3先合并同类项，再求值，其中x=-4132在括号内填上适当的项：( )-9y+( )+2y2+3y-4=11y2-( )+13133在括号内填上适当的项：(-x+y+z)(x+y-z)=y-( )y+( )134在括号内填上适当的项：(3x2+xy-7y2)-( )=y2-2xy-x2135在括号内填上适当的项：(1)x2-xy+y-1=x2-( )；(2)( )+6x-7-4x2+( )-( )=x2-2x+1136计算4x2-3x+4(1-x)-x2-2(4x2-1)的值137化简：138用竖式计算(-x+5+2x4-6x3)-(3x4+2x2-3x3-7)139A=11x3+8x2-6x+2，B=7x3-x2+x+3，求2(3A-2B)