\(\frac{2006\cdot2007-1997}{2006\cdot2005+2015}\)

\(=\frac{2006\cdot2005+2006+2006-1997}{2006\cdot2005+2015}\)

\(=\frac{2006\cdot2005+4012-1997}{2006\cdot2005+2015}\)

\(=\frac{2006\cdot2005+2015}{2006\cdot2005+2015}=1.\)

Đầu bài như này mới đúng mk sửa cho rồi nha

Thank bn Dương Đức Hiệp nhiều nha

Phân số à ?

\(\frac{2006\cdot2007-1997}{2006\cdot2005+2015}\)

\(=\frac{2006\cdot2005+2006\cdot2-1997}{2006\cdot2005+2015}\)

\(=\frac{2006\cdot2005+4012-1997}{2006\cdot2005+2015}\)

\(=\frac{2006\cdot2005+2015}{2006\cdot2005+2015}=1.\)

Đề đúng là \(D=\frac{2006\times2007-2593}{2005\times2006+1419}\) mới tính được nhé bạn!

\(D=\frac{2006\times2007-2593}{2005\times2006+1419}\)

\(=\frac{2006\times2005+2006\times2-2593}{2005\times2006+1419}\)

\(=\frac{2006\times2005+1419}{2006\times2005+1419}=1\)

cảm ơn bạn nhé

Ta có : \(\frac{x^2-2008}{2007}+\frac{x^2-2007}{2006}+\frac{x^2-2006}{2005}=\frac{x^2-2005}{2004}+\frac{x^2-2004}{2003}+\frac{x^2-2003}{2002}\)

=> \(\frac{x^2-2008}{2007}+1+\frac{x^2-2007}{2006}+1+\frac{x^2-2006}{2005}+1=\frac{x^2-2005}{2004}+1+\frac{x^2-2004}{2003}+1+\frac{x^2-2003}{2002}+1\)

=> \(\frac{x^2-2008}{2007}+\frac{2007}{2007}+\frac{x^2-2007}{2006}+\frac{2006}{2006}+\frac{x^2-2006}{2005}+\frac{2005}{2005}=\frac{x^2-2005}{2004}+\frac{2004}{2004}+\frac{x^2-2004}{2003}+\frac{2003}{2003}+\frac{x^2-2003}{2002}+\frac{2002}{2002}\)

=> \(\frac{x^2-1}{2007}+\frac{x^2-1}{2006}+\frac{x^2-1}{2005}=\frac{x^2-1}{2004}+\frac{x^2-1}{2003}+\frac{x^2-1}{2002}\)

=> \(\frac{x^2-1}{2007}+\frac{x^2-1}{2006}+\frac{x^2-1}{2005}-\frac{x^2-1}{2004}-\frac{x^2-1}{2003}-\frac{x^2-1}{2002}=0\)

=> \(\left(x^2-1\right)\left(\frac{1}{2007}+\frac{1}{2006}+\frac{1}{2005}-\frac{1}{2004}-\frac{1}{2003}-\frac{1}{2002}\right)=0\)

=> \(x^2-1=0\)

=> \(x^2=1\)

=> \(x=\pm1\)

Vậy phương trình có 2 nghiệm là x = 1, x = -1 .

Thanks bn

https://hentaiz.net/

2007-(2005-x)=2006

2005-x=2007-2006

2005-x=1

x=2005-1

x=2004

x = 2004