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\(\frac{x+5}{2015}+\frac{x+6}{2014}+\frac{x+7}{2013}+\frac{x+8}{2012}+\frac{x+9}{2011}+5=0\)
\(\Rightarrow1+\frac{x+5}{2015}+1+\frac{x+6}{2014}+1+\frac{x+7}{2013}+1+\frac{x+8}{2012}+1+\frac{x+9}{2011}=0\)
\(\Rightarrow\frac{x+2020}{2015}+\frac{x+2020}{2014}+\frac{x+2020}{2013}+\frac{x+2020}{2012}+\frac{x+2020}{2011}=0\)
\(\Rightarrow\left(x+2020\right)\left(\frac{1}{2015}+\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}+\frac{1}{2011}\right)=0\)
\(\Rightarrow x+2020=0\)
\(\Rightarrow x=-2020\)
Study well
Lời giải:
Ta có:
\(f(x)=x\left(\frac{x^{2013}}{3}-\frac{x^{2014}}{5}+\frac{x^{2015}}{7}+\frac{x^2}{2}\right)-\left(\frac{x^{2014}}{3}-\frac{x^{2015}}{5}+\frac{x^{2016}}{7}+\frac{x^2}{2}\right)\)
\(f(x)=\frac{x^{2014}}{3}-\frac{x^{2015}}{5}+\frac{x^{2016}}{7}+\frac{x^3}{2}-\left(\frac{x^{2014}}{3}-\frac{x^{2015}}{5}+\frac{x^{2016}}{7}+\frac{x^2}{2}\right)\)
\(f(x)=\frac{x^3}{2}-\frac{x^2}{2}=\frac{x^2(x-1)}{2}\)
Với mọi giá trị nguyên của $x$ thì $(x-1)x$ là tích của hai số nguyên liên tiếp nên luôn chia hết cho $2$
Do đó: \(x^2(x-1)\vdots 2\Rightarrow f(x)=\frac{x^2(x-1)}{2}\in\mathbb{Z}\) với mọi gt nguyên của $x$ (đpcm)
Tham khảo ở đây nhé bn: olm.vn/hoi-dap/question/686545.html, mk lm r`
Ta có: \(\frac{x+4}{2000}+\frac{x+3}{2001}=\frac{x+2}{2002}+\frac{x+1}{2003}\)
\(\Rightarrow\frac{x+4}{2000}+1+\frac{x+3}{2001}+1=\frac{x+2}{2002}+1+\frac{x+1}{2003}+1\)
\(\Rightarrow\frac{x+2004}{2000}+\frac{x+2004}{2001}=\frac{x+2004}{2002}+\frac{x+2004}{2003}\)
\(\Rightarrow\frac{x+2004}{2000}+\frac{x+2004}{2001}-\frac{x+2004}{2002}-\frac{x+2004}{2003}=0\)
\(\Rightarrow\left(x+2004\right)\left(\frac{1}{2000}+\frac{1}{2001}-\frac{1}{2002}-\frac{1}{2003}\right)=0\)
Mà \(\frac{1}{2000}+\frac{1}{2001}-\frac{1}{2002}-\frac{1}{2003}\ne0\)
\(\Rightarrow x+2004=0\)
\(\Rightarrow x=-2004\)
Vậy .........................................
\(\frac{x+1}{2015}\)+\(\frac{x+2}{2014}\)+\(\frac{x+3}{2013}\)+\(\frac{x+4}{2012}\)=44
\(\frac{x+1}{2015}\)+1+\(\frac{x+2}{2014}\)+1+\(\frac{x+3}{2013}\)+1+\(\frac{x+4}{2012}\)+1=44+4
\(\frac{x+2016}{2015}\)+\(\frac{x+2016}{2014}\)+\(\frac{x+2016}{2013}\)+\(\frac{x+2016}{2012}\)=48
(x+2016)(\(\frac{1}{2015}\)+\(\frac{1}{2014}\)+\(\frac{1}{2013}\)+\(\frac{1}{2012}\))=48
tu lam tiep.Nho k tui voi
\(\frac{x+4}{2013}+\frac{x+3}{2014}=\frac{x+2}{2015}+\frac{x+1}{2016}\)
\(\Rightarrow\frac{x+4}{2013}+1+\frac{x+3}{2014}+1=\frac{x+2}{2015}+1+\frac{x+1}{2016}+1\)
\(\Rightarrow\frac{x+2017}{2013}+\frac{x+2017}{2014}=\frac{x+2017}{2015}+\frac{x+2017}{2016}\)
\(\Rightarrow\frac{x+2017}{2013}+\frac{x+2017}{2014}-\frac{x+2017}{2015}-\frac{x+2017}{2016}=0\)
\(\Rightarrow\left(x+2017\right)\left(\frac{1}{2013}+\frac{1}{2014}-\frac{1}{2015}-\frac{1}{2016}\right)=0\)
\(Do\)\(\frac{1}{2013}+\frac{1}{2014}-\frac{1}{2015}-\frac{1}{2016}\ne0\)
\(\Rightarrow x+2017=0\)
\(\Rightarrow x=-2017\)
Vậy \(x=-2017\)
bạn bấm vào "đúng 0" là sẽ có đáp án hiện ra
\(\frac{x+4}{2012}+\frac{x+3}{2013}=\frac{x+2}{2014}+\frac{x+1}{2015}.\)
\(\left(\frac{x+4}{2012}+1\right)+\left(\frac{x+3}{2013}+1\right)=\left(\frac{x+2}{2014}+1\right)+\left(\frac{x+1}{2015}+1\right)\)
\(\left(\frac{x+4}{2012}+\frac{2012}{2012}\right)+\left(\frac{x+3}{2013}+\frac{2013}{2013}\right)=\left(\frac{x+2}{2014}+\frac{2014}{2014}\right)+\left(\frac{x+1}{2015}+\frac{2015}{2015}\right)\)
\(\frac{x+2016}{2012}+\frac{x+2016}{2013}=\frac{x+2016}{2014}+\frac{x+2016}{2015}\)
\(\frac{x+2016}{2012}+\frac{x+2016}{2013}-\frac{x+2016}{2014}-\frac{x+2016}{2015}=0\)
\(\left(x+2016\right)\left(\frac{1}{2012}+\frac{1}{2013}-\frac{1}{2014}-\frac{1}{2015}\right)=0\)
\(\Rightarrow x+2016=0\Rightarrow x=\left(-2016\right)\)
Cộng 1 vào mỗi ps
\(\frac{x+5}{2015}+1+\frac{x+6}{2014}+1+\frac{x+7}{2013}+1=0\)
\(\Rightarrow\frac{x+2020}{2015}+\frac{x+2020}{2014}+\frac{x+2020}{2013}=0\)
\(\Rightarrow\left[x+2020\right]\left[\frac{1}{2015}+\frac{1}{2014}+\frac{1}{2013}\right]=0\)
Mà \(\frac{1}{2015}+\frac{1}{2014}+\frac{1}{2013}\ne0\Rightarrow x+2020=0\)
=> x = -2020
Cảm ơn bạn nhiều nha