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\(\frac{1-x}{2015}+\frac{2-x}{1007}+\frac{3-x}{671}=\frac{1992-x}{4}\)
\(\left(\frac{1-x}{2015}+1\right)+\left(\frac{2-x}{1007}+2\right)+\left(\frac{3-x}{671}+3\right)=\frac{1992-x}{4}+6\)
\(\left(\frac{2016-x}{2015}+\frac{2016-x}{1007}+\frac{2016-x}{671}\right)=\frac{2016-x}{4}\)
\(\Leftrightarrow\left(2016×x\right)×\left(\frac{1}{2015}+\frac{1}{1007}+\frac{1}{671}-\frac{1}{4}\right)=0\)
Vì\(\frac{1}{2015}+\frac{1}{1007}+\frac{1}{671}-\frac{1}{4}\ne0\)
\(\Rightarrow2016-x=0\)
\(\Rightarrow x=2016\)
Chúc bạn học tốt!
=13/12x14/13x15/14x16/15x...x2006/2005x2007/2006x2008/2007
=2008/12
=502/3
A = 1\(\dfrac{1}{12}\) \(\times\) 1\(\dfrac{1}{13}\) \(\times\) 1\(\dfrac{1}{14}\) \(\times\) 1\(\dfrac{1}{15}\) \(\times\) ... \(\times\) 1\(\dfrac{1}{2005}\) \(\times\) 1\(\dfrac{1}{2006}\) \(\times\) 1\(\dfrac{1}{2007}\)
A = ( 1 + \(\dfrac{1}{12}\)) \(\times\) ( 1 + \(\dfrac{1}{13}\)) \(\times\) ( 1 + \(\dfrac{1}{14}\)) \(\times\)...\(\times\) ( 1 + \(\dfrac{1}{2006}\))\(\times\)(1+\(\dfrac{1}{2007}\))
A = \(\dfrac{13}{12}\) \(\times\) \(\dfrac{14}{13}\) \(\times\) \(\dfrac{15}{14}\) \(\times\) ...\(\times\) \(\dfrac{2007}{2006}\) \(\times\) \(\dfrac{2008}{2007}\)
A = \(\dfrac{13\times14\times15\times...\times2007}{13\times14\times15\times...\times2007}\) \(\times\) \(\dfrac{2008}{12}\)
A = 1 \(\times\) \(\dfrac{502}{3}\)
A = \(\dfrac{502}{3}\)
Đảm bao là đúng :
3/x = 1/4
3 : x = 1/4
x = 3 : 1/4
x = 12
Tíc mình cái nha , bài này mình trả lời đúng rồi đó
\(\frac{3}{12}=\frac{1}{4}\)
Vậy x là 12 vì \(\frac{3}{12}\) rút gọn bằng \(\frac{1}{4}\)
ai k mình mình k lại
\(\dfrac{4}{x}=\dfrac{1}{5}\)
x = \(\dfrac{4\times5}{1}\)= 20
`4/x=1/5`
`=>x=4:1/5`
`=>x=4xx1/5`
`=>x=4/5`
Vậy `x=4/5`