求20道初二的化简求值题急用
求20道初二的化简求值题急用
1．(3a2-4ab-5b2)-(2b2-5a2+2ab)-(-6ab)．
2．xy-(2xy-3z)+(3xy-4z)．
3．(-3x3+2x2-5x+1)-(5-6x-x2+x3)．
4．3x-(2x-4y-6x)+3(-2z+2y)．
5．(-x2+4+3x4-x3)-(x2+2x-x4-5)．
6．若A=5a2-2ab+3b2,B=-2b2+3ab-a2,计算A+B．
7．5m2n+(-2m2n)+2mn2-(+m2n)．
8．2(x2-2xy+y2-3)+(-x2+y2)-(x2+2xy+y2)．
9．2(a2-ab-b2)-3(4a-2b)+2(7a2-4ab+b2)．
10．求(3x2y-2xy2)-(xy2-2x2y),其中x=-1,y=2．
11．已知|x+1|+(y-2)2=0,求代数式5(2x-y)-3(x-4y)的值．
12．当P=a2+2ab+b2,Q=a2-2ab-b2时,求P-[Q-2P-(P-Q)]．
13．求2x2-｛-3x+5+[4x2-(3x2-x-1)]｝的值,其中x=-3．
14．当x=-2,y=-1,z=3时,求5-｛2x2y-[3-(4xy2-x2y)]｝的值．
15．已知A=x3-5x2,B=x2-6x+3,求A-3(-2B)．
16．去括号：｛-[-(a+b)]｝-｛-[-(a-b)]｝．
17．去括号：-[-(-x)-y]-[+(-y)-(+x)]．
18．合并同类项：5m2n+5mn2-mn+3m2n-6mn2-8mn．
求20道初二的化简求值题
1、-9(x-2)-y(x-5)
（1）化简整个式子。
（2）当x=5时，求y的解。
2、5(9+a)×b-5(5+b)×a
（1）化简整个式子。
（2）当a=5/7时，求式子的值。
3、62g+62(g+b)-b
（1）化简整个式子。
（2）当g=5/7时，求b的解。
4、3(x+y)-5(4+x)+2y
（1）化简整个式子。
5、(x+y)(x-y)
（1）化简整个式子。
6、2ab+a×a-b
（1）化简整个式子。
7、5.6x+4(x+y)-y
（1）化简整个式子。
8、6.4(x+2.9)-y+2(x-y)
（1）化简整个式子。
9、(2.5+x)(5.2+y)
（1）化简整个式子11．(2x2-3xy+4y2)+(x2+2xy-3y2)=______．
．2a-(3a-2b+2)+(3a-4b-1)=______．
．-6x2-7x2+15x2-2x2＝______．
．2x-(x+3y)-(-x-y)-(x-y)＝______．
．2x+2y-[3x-2(x-y)]=______．
．5-(1-x)-1-(x-1)=______．
．( )+(4xy+7x2-y2)=10x2-xy．
．(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3． 已知A=x3-2x2+x-4，B=2x3-5x+3，计算A+B=______．
．已知A=x3-2x2+x-4，B=2x3-5x+3，计算A-B=______．
．若a=-0.2，b=0.5，代数式-(|a2b|-|ab2|)的值为______．
初二化简求值题
解：原式可化为
[(15x²+16xy+4y²)+(x²-4y²)]/4x
=(16x²+16xy)/4x
=4x+4y
代入得
4×2+4×3=20
初二一道化简求值题.
a²+9b²-6ab+9a²+b²+6ab-a²-25b²-10ab+a²+25b²-10ab=10a²+10b²-20ab=10(a²-2ab+b²)=10(a-b)²=10(-8 - -6)²=40
初二上化简求值题100
1、已知A,B是方程x^2+2x-5=0的两个实数根,
求(A^2+2AB+2A)(B^2+2AB+2B)的值.
由A,B是方程x^2+2x-5=0的两个实数根得：
AB=-5,A+B=-2
A^2+2AB+2A)(B^2+2AB+2B)
=AB（A+2B+2）（B+2A+2）
=-5（-2+B+2）（-2+A+2）
=-5AB
=25
2、1/2(x+y+z)方+1/2(x-y-z)(x-y+z)-z(x+y),其中x-y=6,xy=21.要详细步骤
化简得：
1/2(x+y+z)方+1/2(x-y-z)(x-y+z)-z(x+y)=
1/2[(x+y)方+2z(x+y)+z方]+1/2[(x-y)方-z方]-z(x+y)=
1/2(x+y)方+1/2(x-y)方=x方＋y方
由x-y=6,xy=21得,x方＋y方＝（x-y）方＋2xy＝78
3、a^2-ab+2b^2=3 求2ab-2a^2-4b^2-7的值
2ab-2a^2-4b^2-7
=2(ab-a^2-2b^2)-7
=-2(a^2-ab+2b^2)-7
=(-2)*3-7
=-6-7=-13
4、若A=2x^2+3xy-2x-3,B=-x^2+xy+2,且3A+6B的值与x无关,求y的值
3A+6B=6x^2+9xy-6x-9-6x^2+6xy+12
=15xy-6x+3
=x(15y-6)+3
5、9x+6x^2 -3(x-2/3x^2).其中x=-2
9x+6x? -3(x-2/3x?)
=9x+6x?-3x+2x?
=8x?+6x
=8×(-2)?+6×(-2)
=32-12
=20
6、1/4(-4x^2+2x-8)-(1/2x-1),其中x=1/2
1/4(-4x?+2x-8)-(1/2x-1)
=-x?+1/2x-2-1/2x+1
=-x?-1
=-(1/2)?-1
=-1/4-1
=-5/4
7、3x'y-[2x'y-(2-x'z)-4x'z]-,其中x=-2,y=-3,z=1,
:3x'y-[2x'y-(2-x'z)-4x'z]-
=3x'y-2x'y+2-x'z+4x'z-
=x'y-+3x'z
=4*(-3)-2*3*1+3*4*1
=-12-6+12
=-6
8、(5a^2-3b^2)+(a^2+b^2)-(5a^2+3b^2),其中a=-1,b=1
=5a^2-3b^2+a^2+b^2-5a^2-3b^2
=a^2-5b^2
=(-1)^2-5*1^2
=1-5
=-4
9、2(a^2b+ab^2)-2(a^2 b-1)-2ab^2 -2其中a=-2,b=2
=2a^2b+2ab^2-2a^2b+2-2ab^2-2
=0
10、(X-2分之1Y-1)(X-2分之1Y+1)-(X-2分之1Y-1)的平方
其中X=1.7,Y=3.9(先化简再求值)
[(X-2分之1Y)-1][(X+2分之1Y)+1]-(X-2分之1Y-1)平方
=(X+2分之1Y)平方-1-(X-2分之1Y)平方+2(X-2分之1Y)-1
=(X+2分之1Y)平方-(X-2分之1Y)平方+2(X-2分之1Y)-2
=2XY+2X-Y-2
=3.9*2.4+1.4
=10.76
化间求值: 下面的你自己求吧```
1、-9(x-2)-y(x-5)
（1）化简整个式子.
（2）当x=5时,求y的解.
2、5(9+a)×b-5(5+b)×a
（1）化简整个式子.
（2）当a=5/7时,求式子的值.
3、62g+62(g+b)-b
（1）化简整个式子.
（2）当g=5/7时,求b的解.
4、3(x+y)-5(4+x)+2y
（1）化简整个式子.
5、(x+y)(x-y)
（1）化简整个式子.
6、2ab+a×a-b
（1）化简整个式子.
7、5.6x+4(x+y)-y
（1）化简整个式子.
8、6.4(x+2.9)-y+2(x-y)
（1）化简整个式子.
9、(2.5+x)(5.2+y)
（1）化简整个式子.
10、9.77x-(5-a)x+2a
(5a^2-3b^2)+(a^2+b^2)-(5a^2+3b^2),其中a=-1,b=1
=5a^2-3b^2+a^2+b^2-5a^2-3b^2
=a^2-5b^2
=(-1)^2-5*1^2
=1-5
=-4
2(a^2b+ab^2)-2(a^2 b-1)-2ab^2 -2其中a=-2,b=2
=2a^2b+2ab^2-2a^2b+2-2ab^2-2
=0
x+7-(-36+8^2)/2=[-(-8x)+7^4]/3*(8^2-6x)
(a-7)-(-98a)+7a=[(3.2*5a)2^5]/10
(89/2+5x)+35/6x=[3*(-9+5)+2^3]/5+7x
[3X+(-189+5^2)/3]/8=521/2
4y+[119*(-5^3y+8/7)-8/3]=22/11
(3X*189)+{5*6+[-5/8*(-65*8^3)]+9/2}
7(2x-1)-3(4x-1)=4(3x+2)-1
(5y+1)+ (1-y)= (9y+1)+ (1-3y)
[-6(-7^4*8)-4]=x+2
20%+(1-20%)(320-x)=320×40%
2(x-2)+2=x+1
2(x-2)-3(4x-1)=9(1-x)
11x+64-2x=100-9x
15-(8-5x)=7x+(4-3x)
3(x-7)-2[9-4(2-x)]=22
3/2[2/3(1/4x-1)-2]-x=2
2x+7^2=157
9x+6x? -3(x-2/3x?)
=9x+6x?-3x+2x?
=8x?+6x
=8×(-2)?+6×(-2)
=32-12
=20
1/4(-4x?+2x-8)-(1/2x-1)
=-x?+1/2x-2-1/2x+1
=-x?-1
=-(1/2)?-1
=-1/4-1
=-5/4
3．3ab-4ab+8ab-7ab+ab=______．
4．7x-(5x-5y)-y=______．
5．23a3bc2-15ab2c+8abc-24a3bc2-8abc=______．
6．-7x2+6x+13x2-4x-5x2=______．
7．2y+(-2y+5)-(3y+2)＝______．
11．(2x2-3xy+4y2)+(x2+2xy-3y2)=______．
12．2a-(3a-2b+2)+(3a-4b-1)=______．
13．-6x2-7x2+15x2-2x2＝______．
14．2x-(x+3y)-(-x-y)-(x-y)＝______．
16．2x+2y-[3x-2(x-y)]=______．
17．5-(1-x)-1-(x-1)=______．
18．( )+(4xy+7x2-y2)=10x2-xy．
19．(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3．
21．已知A=x3-2x2+x-4,B=2x3-5x+3,计算A+B=______．
22．已知A=x3-2x2+x-4,B=2x3-5x+3,计算A-B=______．
23．若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．若-3a3b2与5ax-1by+2是同类项,则x=______,y=______．
28．(-y+6+3y4-y3)-(2y2-3y3+y4-7)＝______．
29．化简代数式4x2-[7x2-5x-3(1-2x+x2)]的结果是______．
30．2a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( )．
31．3a-(2a-3b)+3(a-2b)-b=______．
32．化简代数式x-[y-2x-(x+y)]等于______．
33．[5a2+( )a-7]+[( )a2-4a+( )]=a2+2a+1．
34．3x-[y-(2x+y)]=______．
35．化简|1-x+y|-|x-y|(其中x＜0,y＞0)等于______．
36．已知x≤y,x+y-|x-y|=______．
37．已知x＜0,y＜0,化简|x+y|-|5-x-y|=______．
38．4a2n-an-(3an-2a2n)＝______．
39．若一个多项式加上-3x2y+2x2-3xy-4得
2x2y+3xy2-x2+2xy,
则这个多项式为______．
40．-5xm-xm-(-7xm)+(-3xm)=______．
初二化简求值
a²+1=3a
两边除以a
a+1/a=3
两边平方
a²+2+1/a²=9
a²+1/a²=7
则(a-1/a)²
=a²-2+1/a²
=7-2
=5
所以原式=[(a+1/a)(a-1/a)](a-1/a)
=(a+1/a)(a-1/a)²
=3*5
=15
X+Y=-4.(X+Y)^2=X^2+Y^2+2XY=16.XY=-12.X^2+Y^2=40.Y+1/X+1+X+1/Y+1=(Y+1)^2+(X+1)^2/(X+1)(Y+1)=自己乘开就行,再把上面的数带到你乘开的式子里=-34/15
[数学题]初二,化简求值
x^2+2xy+y^2/x^2-y^2除以x^2+xy/xy-y^2
=(x＋y)²／(x＋y)(x－y) ÷x(x＋y)／y(x－y)
=(x＋y)／(x－y) × y(x－y)／x(x＋y)
=y／x
再将X=1
Y=-2011代入
原式=y／x
=﹣2011
初二一道化简求值
分母是-ab
原式=(a²b²-ab-2-2a²b²+2)÷(-ab)
=(a²b²+ab)÷(ab)
=ab+1
=-2+1
=-1
求初二数学化简求值30道
没有！！
绛旓細姹20閬撳垵浜岀殑鍖栫畝姹傚奸鎬ョ敤 1锛(3a2-4ab-5b2)-(2b2-5a2+2ab)-(-6ab)锛 2锛巟y-(2xy-3z)+(3xy-4z)锛 3锛(-3x3+2x2-5x+1)-(5-6x-x2+x3)锛 4锛3x-(2x-4y-6x)+3(-2z+2y)锛 5锛(-x2+4+3x4-x3)-(x2+2x-x4-5)锛 6锛庤嫢A=5a2-2ab+3b2,B=-2b2+3...
绛旓細1銆-9(x-2)-y(x-5) 锛1锛鍖栫畝鏁翠釜寮忓瓙.锛2锛夊綋x=5鏃,姹倅鐨勮В.2銆5(9+a)脳b-5(5+b)脳a 锛1锛夊寲绠鏁翠釜寮忓瓙.锛2锛夊綋a=5/7鏃,姹傚紡瀛愮殑鍊.3銆62g+62(g+b)-b 锛1锛夊寲绠鏁翠釜寮忓瓙.锛2锛夊綋g=5/7鏃,姹俠鐨勮В.4銆3(x+y)-5(4+x)+2...
绛旓細98.宸茬煡A=a2+2b2-3c2,B=-b2-2c2+3a2,C=c2+2a2-3b2,姹(A-B)+C. 99.姹(3x2y-2xy2)-(xy2-2x2y),鍏朵腑x=-1,y=2. 101.宸茬煡|x+1|+(y-2)2=0,姹備唬鏁板紡5(2x-y)-3(x-4y)鐨勫. 106.褰揚=a2+2ab+b2,Q=a2-2ab-b2鏃,姹侾-[Q-2P-(P-Q)]. 107.姹2x2-{-3x+5+[4x2-...
绛旓細x^2-3x-1=0,x-3-1/x=0 (x涓=0)x-1/x=3 (x-1/x)^2=9 x^2+1/x^2-2=9 x^2+1/x^2=11 x^2+1/x^2+2=11+2 x+1/x=鏍13 x^3+1/x^3=(x+1/x)(x^2+1/x^2-1)=鏍13*(11-1)=10鏍13
绛旓細(鍏鍖栫畝鍐姹傚) [(X-2鍒嗕箣1Y)-1][(X+2鍒嗕箣1Y)+1]-(X-2鍒嗕箣1Y-1)骞虫柟 =(X+2鍒嗕箣1Y)骞虫柟-1-(X-2鍒嗕箣1Y)骞虫柟+2(X-2鍒嗕箣1Y)-1 =(X+2鍒嗕箣1Y)骞虫柟-(X-2鍒嗕箣1Y)骞虫柟+2(X-2鍒嗕箣1Y)-2 =2XY+2X-Y-2 =3.9*2.4+1.4 =10.76 鍖栭棿姹傚: 涓嬮潰鐨勪綘鑷繁姹傚惂``` 1銆-9(x-...
绛旓細=20 鏁村紡鍖栫畝姹傚奸鍙婄瓟妗 绠鍗曚竴鐐癸紝鍘诲垎姣嶇殑鏂圭▼涔熻锛岃鏈夌瓟妗堛傝秺澶氳秺濂斤紝鎴戞湁杩藉姞 ,鏈濂芥槸鍘熷垱鐨勶紝鍒嗘瘝鐨勬柟绋嬩篃鏉ョ偣銆傛潵鑷尶鍚嶇敤鎴风殑鎻愰棶 鏈浣崇瓟妗堢敱鎻愰棶鑰呮帹鑽 1.锛3X+2Y)+(4X+3Y)鍏朵腑X=5,Y+3 瑙ｏ細鍘熷紡=3X+2Y+4X+3Y=7X+5Y 褰揦=5,Y=3鏃 鍘熷紡=5*7+锛-3锛*5+20 2.(5a^...
绛旓細鍒嗗紡瑕佸厛鍥犲紡鍒嗚В锛1 鐢辨潯浠跺厛瑙ｅ嚭a=銆傘傘傦紱a²=3a-1 2 鍒嗗紡=銆愶紙a²锛媋-3锛壝凤紙a锛1锛夈*銆愶紙a-1锛*锛坅²锛媋锛5锛壝凤紙a²-2a锛夈懨凤紙a²-1锛夋妸a²=3a-1浠ｅ叆涓婂紡骞鍖栫畝寰楀埌 銆傘傘=16梅锛坅锛1锛夋妸a=銆傘傘備唬鍏ワ紝寰椼傘傘傦紝鍗冲師鍒嗗紡鐨勫间负銆
绛旓細127.鍖栫畝:2x2-{-3x-[4x2-(3x2-x)+(x-x2)]}.128.鍖栫畝:-(7x-y-2z)-{[4x-(x-y-z)-3x+z]-x}.129.璁＄畻:(+3a)+(-5a)+(-7a)+(-31a)-(+4a)-(-8a).130.鍖栫畝:a3-(a2-a)+(a2-a+1)-(1-a4+a3).131.灏唜2-8x+2x3-13x2-2x-2x3+3鍏堝悎骞跺悓绫婚」,鍐姹傚,鍏朵腑x=-4.132.鍦...
绛旓細绛夊紡涓よ竟閮戒箻浠2/3鍙鍖栫畝涓2x=4/3y+4z 灏2x=4/3y+4z甯﹀叆鈶犲紡鍙彉涓4/3y+4z+z=3y锛屽寲绠鏂圭▼鍙緱3z=y锛 灏3z=y甯﹀叆鈶″紡6z=2y锛岄偅涔堚憽寮忓彲鍙樹负3x=2y+2y锛屽寲绠鍚庡彲寰3x=4y锛寈=3/4y 瑙ｅ嚭褰搙=16鏃讹紝y=12锛寊=4锛屽垯x=16 ...
绛旓細(a+b)(a-b)/ab(a-b)+(a+b)^2/2ab =(a+b)/ab+(a+b)^2/2ab =(a+b)(a+b+2)/2ab =-4/15
