Bai 1: Rut gon bieu thuc:
a, (x2+2)2- (x+2).(x-2).(x2+4)
b, (x+1)2-(x-1)2-3.(x+1).(x-1)
Giup minh voi ! THANK YOU !^^
Những câu hỏi liên quan
giai dum minh bai nay voi :c=x/2x-2+x^2+1/2-2x^2
a)tim x de a co nghia
b)rut gon bieu thuc c
c)tim gia tri cua x de bieu thuc kia =1/2
giúp mình cảm ơn nhìu nha !
rut gon bieu thuc -3/5<x<1/7
B=|-x+1/7|+|-x-3/5|-2/6
help me! giup mk voi minh can gap do
Bai 1: Cho bt
P=(\(\dfrac{x-2}{x^2-1}\)-\(\dfrac{x+2}{x^2+2x+1}\)).(\(\dfrac{1-x^2}{2}\))2
a, Rut gon P
b, Tim x de \(\dfrac{P-4}{5}\)=x
Bai 2:Chung minh bieu thuc A=\(\dfrac{3}{2}\)-\(\dfrac{x}{x^2+x+1}\) luon duong voi moi x
Bài 1:
a: \(P=\left(\dfrac{x-2}{\left(x-1\right)\left(x+1\right)}-\dfrac{x+2}{\left(x+1\right)^2}\right)\cdot\dfrac{\left(x-1\right)^2\cdot\left(x+1\right)^2}{4}\)
\(=\dfrac{x^2-x-2-x^2-x+2}{\left(x-1\right)\left(x+1\right)^2}\cdot\dfrac{\left(x-1\right)^2\cdot\left(x+1\right)^2}{4}\)
\(=\dfrac{-2x}{1}\cdot\dfrac{x-1}{4}=-\dfrac{x\left(x-1\right)}{2}\)
b: Để \(\dfrac{P-4}{5}=x\) thì P-4=5x
=>P=5x+4
\(\Leftrightarrow-\dfrac{x\left(x-1\right)}{2}=5x+4\)
=>-x2+x=10x+8
=>x2-x=-10x-8
=>x2+9x+8=0
=>x=-8(nhận) hoặc x=-1(loại)
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Rut gon bieu thuc A =\(\frac{x+5-5\sqrt{x-1}}{x-1-3\sqrt{x-1}}\)
Giup minh giai bai nay voi .
Cam on
\(A=\frac{\left(x-1\right)-5\sqrt{x-1}+6}{\sqrt{x-1}\cdot\left(\sqrt{x-1}-3\right)}=\frac{\left(\sqrt{x-1}-2\right)\cdot\left(\sqrt{x-1}-3\right)}{\sqrt{x-1}\cdot\left(\sqrt{x-1}-3\right)}\) Đk x\(\ne\) 1;10
\(A=\frac{\sqrt{x-1}-2}{\sqrt{x-1}}=1-\frac{2}{\sqrt{x-1}}\)
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Bai 1: Rut Gon Bieu Thuc :
a, (x2 - 1)3 - (x4+ x2+1) (x2- 1)
b, (x4 - 3x2+ 9) (x2+3) - (3+x2)3
Bai 5 : Tim GTLN hoac GTNN neu co cua cac bieu thuc
a, A x2-2x-1
b, B 4x2+4x+5
c, C 2x - x2- 4
GIUP MINH VOI CAM ON NHIEU !^^
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Bai 1: Rut Gon Bieu Thuc :
a, (x2 - 1)3 - (x4+ x2+1) (x2- 1)
b, (x4 - 3x2+ 9) (x2+3) - (3+x2)3
Bai 5 : Tim GTLN hoac GTNN neu co cua cac bieu thuc
a, A = x2-2x-1
b, B = 4x2+4x+5
c, C = 2x - x2- 4
GIUP MINH VOI CAM ON NHIEU !^^ 
Bài 1:
\(a,\left(x^2-1\right)^3-\left(x^4+x^2+1\right)\left(x^2-1\right)\)
\(=x^6-3x^4+3x^2-1-x^6+1\)
\(=-3x^2\left(x^2-1\right)\)
\(b,\left(x^4-3x^2+9\right)\left(x^2+3\right)-\left(3+x^2\right)^3\)
\(=x^6+27-27-27x^2-9x^4-x^6\)
\(=-9x^2\left(3-x^2\right)\)
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Bài 5:
\(A=x^2-2x+1\)
\(=\left(x^2-2x+1\right)-2\)
\(=\left(x-1\right)^2-2\)
Với mọi giá trị của x ta có:
\(\left(x-1\right)^2\ge0\Rightarrow\left(x-1\right)^2-2\ge-2\)
Vậy Min A = -2
Để A = -2 thì \(x-1=0\Rightarrow x=1\)
b, \(B=4x^2+4x+5\)
\(=\left(4x^2+4x+1\right)+4\)
\(=\left(2x+1\right)^2+4\)
Với mọi giá trị của x ta có:
\(\left(2x+1\right)^2\ge0\Rightarrow\left(2x+1\right)^2+4\ge4\)
Vậy Min B = 4
Để B = 4 thì \(2x+1=0\Rightarrow2x=-1\Rightarrow x=-\dfrac{1}{2}\)
c, \(C=2x-x^2-4\)
\(=-\left(x^2-2x+1\right)-3\)
\(=-\left(x-1\right)^2-3\)
Với mọi giá trị của x ta có:
\(\left(x-1\right)^2\ge0\Rightarrow-\left(x-1\right)^2\le0\Rightarrow-\left(x-1\right)^2-3\le-3\)Vậy Max C = -3
để C = -3 thì \(x-1=0\Rightarrow x=1\)
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B1: rut gon bieu thuc
a, (x+y)^2-4(x-y)^2
b, 2(x-y)(x+y)+(x+y)^2+(x-y)^2
B2: tim X
a, (2X-1)^2-4(X+2)^2=9
b, 3(X-1)^2-3X(X-5)=21
B3: Cho bieu thuc
M=(x+3)^3-(x-1)^3+12x(x-1)
a, Rut gon bieu thuc tren
b, Tinh gia tri M tai x=-2/3
c, Tim x de M=16
1)a)=>x2+y2+2xy-4(x2-y2-2xy)
=>x2+y2+2xy-4.x2+4y2+8xy
=>-3.x2+5y2+10xy
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Bo dau ngoac roi rut gon bieu thuc :
A= a .( 5-b) + b . ( a- 5) - (5a + 3b )
B = ( x-1 ) . (x-2) - ( x2 + x + 8 )
Bai 1)Cho bieu thuc Afrac{x+y-2sqrt{xy}}{x-y}a)Tim dieu kien de A co nghiab)Rut gon Ac)Tinh A biet x3+2sqrt{2}va y3-2sqrt{2}Bai 2) Cho bieu thuc Bfrac{x-3}{sqrt{x-1}-sqrt{2}}a)Tim dieu kien de B co nghiab)Rut gon Bc) Tinh B voi x4left(2-sqrt{3}right)d)Tim x de B co gia tri nho nhat
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Bai 1)Cho bieu thuc A=\(\frac{x+y-2\sqrt{xy}}{x-y}\)
a)Tim dieu kien de A co nghia
b)Rut gon A
c)Tinh A biet x=\(3+2\sqrt{2}\)va y=\(3-2\sqrt{2}\)
Bai 2) Cho bieu thuc B=\(\frac{x-3}{\sqrt{x-1}-\sqrt{2}}\)
a)Tim dieu kien de B co nghia
b)Rut gon B
c) Tinh B voi x=\(4\left(2-\sqrt{3}\right)\)
d)Tim x de B co gia tri nho nhat
a) A có nghĩa\(\Leftrightarrow x-y\ne0\Leftrightarrow x\ne y\)
b) \(A=\frac{x+y-2\sqrt{xy}}{x-y}=\frac{\left(\sqrt{x-\sqrt{y}}\right)^2}{\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{x}-\sqrt{y}\right)}=\frac{\sqrt{x}-\sqrt{y}}{\sqrt{x}+\sqrt{y}}\)
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Giup minh nhe!!
1. Rut gon bieu thuc:
a) Asqrt{11-6sqrt{2}}+3+sqrt{2}
b) Bsqrt{12+2sqrt{11}}+sqrt{12-2sqrt{11}}
2. Rut gon bieu thuc:
a) Asqrt{x-2+2sqrt{x-3}}+sqrt{x+6+6sqrt{x-3}},voix3
3. Tim GTNN cua bieu thuc:
a) Asqrt{4x^2-12x+9}+sqrt{x^2-10x+25}+sqrt{9x^2-6x+1}+sqrt{16x^2-72x+81}
b) Bdfrac{1}{2}sqrt{x^2}+sqrt{x^2-2x+1}
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Giup minh nhe!!
1. Rut gon bieu thuc:
a) \(A=\sqrt{11-6\sqrt{2}}+3+\sqrt{2}\)
b) \(B=\sqrt{12+2\sqrt{11}}+\sqrt{12-2\sqrt{11}}\)
2. Rut gon bieu thuc:
a) \(A=\sqrt{x-2+2\sqrt{x-3}}+\sqrt{x+6+6\sqrt{x-3}},voix>=3\)
3. Tim GTNN cua bieu thuc:
a) \(A=\sqrt{4x^2-12x+9}+\sqrt{x^2-10x+25}+\sqrt{9x^2-6x+1}+\sqrt{16x^2-72x+81}\)
b) \(B=\dfrac{1}{2}\sqrt{x^2}+\sqrt{x^2-2x+1}\)
1)
a)
\(\sqrt{11-6\sqrt{2}}=\sqrt{2-2.3.\sqrt{2}+9}=\left|\sqrt{2}-3\right|=3-\sqrt{2}\)
\(A=3-\sqrt{2}+3+\sqrt{2}=6\)
b)
\(B^2=24+2\sqrt{12^2-4.11}=24+2\sqrt{100}=24+20=44\)
\(B=\sqrt{44}=2\sqrt{11}\)
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