2006 x 2007 - 1997 / 2006 x 2005 + 2015
= 2006 x ( 2005 + 2 ) - 1997 / 2006 x 2005 + 2015'
= 2006 x 2005 + 2006 x 2 - 1997 / 2006 x 2005 + 2015
= 2006 x 2005 + 4012 - 1997 / 2006 x 2005 + 2015
= 2006 x 2005 + 2015 / 2006 x 2005 + 2015
= 1
\(\frac{2006x2007-1997}{2006x2005+2015}=1\)
~~~ nếu thấy đúng thì tk mk nha các bn ~~~
\(\frac{2006\cdot2007-1997}{2006\cdot2005+2015}\)=\(\frac{2006\cdot\left(2005+2\right)-1997}{2006\cdot2005+2015}\)=\(\frac{2006\cdot2005+4032-1997}{2006\cdot2005+2015}\)=\(\frac{2006\cdot2005+2015}{2006\cdot2005+2015}\)=1
\(\frac{2006.\left(2005+2\right)-1997}{2006.2005+2006+9}\)
=\(\frac{2006.2005+2006.2-1997}{2006.2005+2006.1+9}\)
=\(\frac{4012-1997}{2015}\)=\(\frac{2015}{2015}\)=\(1\)
\(\frac{2006.2007-1997}{2006.2005+2015}\)
\(=\frac{2006.\left(2007-2\right)-1997}{2006.2005+2015}\)
\(=\frac{2006.2005-1997}{2006.2005+2015}\)
\(=\frac{2006.2005+\left(2006.2-1997\right)}{2006.2005+2015}\)
\(=\frac{2006.2005+2015}{2006.2005+2015}=1\)