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6 tháng 10 2018

\(A=\left(\frac{x+1}{x-1}-\frac{x-1}{x+1}+\frac{\left(x-1\right)^2}{x^2-1}\right).\frac{x+2003}{x}\)ĐKXĐ: \(x\ne-1;0;1\)

\(A=\frac{\left(x+1\right)^2-\left(x-1\right)^2+\left(x-1\right)^2}{\left(x+1\right)\left(x-1\right)}.\frac{x+2003}{x}\)

\(A=\frac{\left(x+1\right)^2}{\left(x+1\right)\left(x-1\right)}.\frac{x+2003}{x}\)

\(A=\frac{x+1}{x-1}.\frac{x+2003}{x}\)

\(A=\frac{x^2+2004x+2003}{x^2-x}\)

6 tháng 2 2019

a) ĐKXĐ : \(x\ne\pm1\)

\(B=\left(\frac{\left(x+1\right)^2-\left(x-1\right)^2+\left(x^2-4x-1\right)}{x^2-1}\right)\cdot\frac{x-2014}{x-1}\)

\(B=\frac{4x+x^2-4x-1}{x^2-1}\cdot\frac{x-2014}{x+1}\)

\(B=\frac{x^2-1}{x^2-1}\cdot\frac{x-2014}{x+1}=\frac{x-2014}{x+1}\)\

b) B có giá trị nguyên

\(\Leftrightarrow x-2014⋮x+1\)

\(\Leftrightarrow x+1-2015⋮x+1\)

\(\Leftrightarrow2015⋮x+1\)

28 tháng 8 2015

a)ĐKXĐ:

\(x-1\ne0;x+1\ne0;x\ne0\)

\(\Leftrightarrow x\ne1;x\ne-1;x\ne0\)

b)\(K=\left(\frac{x+1}{x-1}-\frac{x-1}{x+1}+\frac{x^2-4x-1}{x^2-1}\right).\frac{x+2003}{x}\)

\(=\left(\frac{x+1}{x-1}-\frac{x-1}{x+1}+\frac{x^2-4x-1}{\left(x-1\right)\left(x+1\right)}\right).\frac{x+2003}{x}\)

\(=\left(\frac{\left(x+1\right)^2}{\left(x-1\right)\left(x+1\right)}-\frac{\left(x-1\right)^2}{\left(x-1\right)\left(x+1\right)}+\frac{x^2-4x-1}{\left(x-1\right)\left(x+1\right)}\right).\frac{x+2003}{x}\)

\(=\frac{x^2+2x+1+x^2-2x+1+x^2-4x-1}{\left(x-1\right)\left(x+1\right)}.\frac{x+2003}{x}\)

\(=\frac{3x^2-4x+1}{\left(x-1\right)\left(x+1\right)}.\frac{x+2003}{x}\)

\(=\frac{3x^2-3x-x+1}{\left(x-1\right)\left(x+1\right)}.\frac{x+2003}{x}\)

\(=\frac{3x.\left(x-1\right)-\left(x-1\right)}{\left(x-1\right)\left(x+1\right)}.\frac{x+2003}{x}\)

\(=\frac{\left(x-1\right)\left(3x-1\right)}{\left(x-1\right)\left(x+1\right)}.\frac{x+2003}{x}\)

\(=\frac{\left(3x-1\right)\left(x+2003\right)}{\left(x+1\right).x}\)

\(=\frac{3x^2+6008x-2003}{x^2+x}\)

câu c bí

 

24 tháng 7 2017

a, dk \(x\ge0.x\ne1\)

\(\left(\frac{1+\sqrt{x}+1-\sqrt{x}}{2\left(1-x\right)}-\frac{x^2+1}{1-x^2}\right)\left(\frac{x+1}{x}\right)\)=\(\left(\frac{1}{1-x}-\frac{x^2+1}{1-x^2}\right)\left(\frac{x+1}{x}\right)\)

 =\(\left(\frac{1+x-x^2-1}{1-x^2}\right)\left(\frac{x+1}{x}\right)=\frac{x\left(1-x\right)\left(x+1\right)}{x\left(1-x\right)\left(1+x\right)}=1\)

phan b,c ban tu lam not nhe dai lam mk ko lam dau  mk co vc ban rui