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5 tháng 4 2020

\(\frac{x+1}{2953}+\frac{x+953}{2001}+\frac{x+2950}{4}>-3\)

\(\Leftrightarrow\frac{x+1}{2953}+\frac{x+953}{2001}+\frac{x+2950}{4}+3>0\)

\(\Leftrightarrow\frac{x+1}{2953}+1+\frac{x+953}{2001}+1+\frac{x+2950}{4}+1>0\)

\(\Leftrightarrow\frac{x+1+2953}{2953}+\frac{x+953+2001}{2001}+\frac{x+2950+4}{4}>0\)

\(\Leftrightarrow\frac{x+2954}{2953}+\frac{x+2954}{2001}+\frac{x+2954}{4}>0\)

\(\Leftrightarrow\left(x+2954\right)\left(\frac{1}{2953}+\frac{1}{2001}+\frac{1}{4}\right)>0\)

Vì \(\frac{1}{2953}+\frac{1}{2001}+\frac{1}{4}>0\)

Nên \(x+2954>0\)

\(\Leftrightarrow x>-2954\)

Vậy .........

11 tháng 5 2018

Giải:

\(\dfrac{x+1}{2953}+\dfrac{x+953}{2001}+\dfrac{x+2950}{4}>-3\)

\(\Leftrightarrow\dfrac{x+1}{2953}+\dfrac{x+953}{2001}+\dfrac{x+2950}{4}+3>0\)

\(\Leftrightarrow\dfrac{x+1}{2953}+1+\dfrac{x+953}{2001}+1+\dfrac{x+2950}{4}+1>0\)

\(\Leftrightarrow\dfrac{x+1+2953}{2953}+\dfrac{x+953+2001}{2001}+\dfrac{x+2950+4}{4}>0\)

\(\Leftrightarrow\dfrac{x+2954}{2953}+\dfrac{x+2954}{2001}+\dfrac{x+2954}{4}>0\)

\(\Leftrightarrow\left(x+2954\right)\left(\dfrac{1}{2953}+\dfrac{1}{2001}+\dfrac{1}{4}\right)>0\)

\(\dfrac{1}{2953}+\dfrac{1}{2001}+\dfrac{1}{4}>0\)

Nên \(x+2954>0\)

\(\Leftrightarrow x>-2954\)

Vậy ...

11 tháng 5 2018

\(\dfrac{x+1}{2953}+\dfrac{x+953}{2001}+\dfrac{x+2950}{4}>3\)

<=>\(\left(\dfrac{x+1}{2953}+1\right)+\left(\dfrac{x+953}{2001}+1\right)+\left(\dfrac{x+2950}{4}+1\right)>0\)

<=>\(\dfrac{x+2954}{2953}+\dfrac{x+2954}{2001}+\dfrac{x+2954}{4}>0\)

<=>\(\left(x+2954\right)\left(\dfrac{1}{2953}+\dfrac{1}{2001}+\dfrac{1}{4}\right)>0\)

\(\dfrac{1}{2953}+\dfrac{1}{2001}+\dfrac{1}{4}>0\) nên \(x+2954>0\) <=> \(x>-2954\)

KL: ...

\(\dfrac{x+1}{2953}+\dfrac{x+953}{2001}+\dfrac{x+2950}{4}>-3\\ \dfrac{x+1}{2953}+\dfrac{x+953}{2001}+\dfrac{x+2950}{4}+3>-3+3\\ \dfrac{x+2954}{2953}+\dfrac{x+2954}{2001}+\dfrac{x+2954}{4}>0\\ \left(x+2954\right)\left(\dfrac{1}{2953}+\dfrac{1}{2001}+\dfrac{1}{4}\right)>0\\ x+2954>0\\ x>-2954\)

a.2mx=0 <=> mx=0

•nếu m=0 thì nghiệm đúng với mọi x

•nếu \(m\ne0\) thì nghiệm đúng với x=0

1 tháng 4 2017

a, \(\Rightarrow\)\(1+\frac{x+3}{2011}\)\(+1+\frac{x+1}{2013}\)\(\ge1+\frac{x+10}{2004}+1+\frac{x+13}{2001}\)

\(\Rightarrow\)\(\frac{2011+x+3}{2011}+\frac{2013+x+1}{2013}\ge\frac{2004+x+10}{2004}+\frac{2001+x+13}{2001}\)

\(\Rightarrow\)\(\frac{2014+x}{2011}+\frac{2014+x}{2013}\ge\frac{2014+x}{2004}+\frac{2014+x}{2001}\)

\(\Rightarrow\)\(\frac{2014+x}{2011}+\frac{2014+x}{2013}-\frac{2014+x}{2004}+\frac{2014+x}{2001}\ge0\)

\(\Rightarrow\)\(\left(2014+x\right)\left(\frac{1}{2011}+\frac{1}{2013}-\frac{1}{2004}-\frac{1}{2001}\right)\)\(\ge0\)

\(do\)\(\frac{1}{2011}+\frac{1}{2013}-\frac{1}{2004}-\frac{1}{2001}< 0\)

\(\Rightarrow\)\(2014+x\le0\)

\(\Rightarrow\)\(x\le-2014\)

23 tháng 3 2019

a) \(\frac{x-1}{2}+\frac{x-2}{3}+\frac{x-3}{4}=\frac{x-4}{5}+\frac{x-5}{6}\)

\(\left(\frac{x-1}{2}+1\right)+\left(\frac{x-2}{3}+3\right)+\left(\frac{x-3}{4}+1\right)=\left(\frac{x-4}{5}+1\right)+\left(\frac{x-5}{6}+1\right)\)

\(\frac{x-1}{2}+\frac{x-1}{3}+\frac{x-1}{4}=\frac{x-1}{5}+\frac{x-1}{6}\)

\(\left(x-1\right)\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}\right)\)=0

\(x-1=0\)

\(x=1\)

2 tháng 12 2017

ĐK : \(\orbr{\begin{cases}x>0\\x< -1\end{cases}}\)

Đặt \(\sqrt{\frac{x+1}{x}}=t>0\)

\(bpt\Leftrightarrow\frac{1}{t^2}-2t>3\Leftrightarrow2t^3+3t^2-1< 0\Leftrightarrow\left(2t-1\right)\left(t+1\right)^2< 0\Leftrightarrow2t-1< 0\)(do \(\left(t+1\right)^2>0\))

       \(\Leftrightarrow t< \frac{1}{2}hay\sqrt{\frac{x+1}{x}}< \frac{1}{2}\Rightarrow\frac{x+1}{x}< \frac{1}{4}\)

Với x >0, ta có: \(\frac{x+1}{x}< \frac{1}{4}\Leftrightarrow4\left(x+1\right)< 1\Leftrightarrow x< -\frac{3}{4}\left(trái.với.gt:x>0\right)\)

Với x<-1 ta có: \(\frac{x+1}{x}< \frac{1}{4}\Rightarrow4\left(x+1\right)>x\Rightarrow x>-\frac{3}{4}\Rightarrow-\frac{3}{4}< x< -1\)

Vậy nghiệm của hệ phương trình là: \(-\frac{3}{4}< x< -1\)

27 tháng 6 2016

cho tam giác abc vuông tại a và đường cao ah =12cm, ch = 5cm. tính sin b sin c

ai giải giúp mình bài toán này với mk đang cần rất gấp

29 tháng 12 2015
  
  
  

 

30 tháng 12 2015

1488

4 tháng 4 2020

\(\frac{x-4}{2000}+\frac{x-3}{2001}+\frac{x-2}{2002}=\frac{x-2002}{2}+\frac{x-2001}{3}+\frac{x-2000}{4}\)

<=> \(\left(\frac{x-4}{2000}-1\right)+\left(\frac{x-3}{2001}-1\right)+\left(\frac{x-2}{2002}-1\right)=\left(\frac{x-2002}{2}-1\right)+\left(\frac{x-2001}{3}-1\right)+\left(\frac{x-2000}{4}-1\right)\)

<=> \(\frac{x-2004}{2000}+\frac{x-2004}{2001}+\frac{x-2004}{2002}=\frac{x-2004}{2}+\frac{x-2004}{3}+\frac{x-2004}{4}\)

<=> (x - 2004)(1/2000 + 1/2001 + 1/2002 - 1/2 - 1/3 - 1/4) = 0

<=> x - 2004 = 0 (vì 1/2000 + 1/2001 + 1/2002 - 1/2 - 1/3 - 1/4 khác 0)

<=> x = 2004

Vậy S = {2004}

4 tháng 4 2020

đề bài \(=\frac{x-2002}{2}+\frac{x-2001}{3}+\frac{x-2000}{4}\)

 \(\Leftrightarrow\frac{x}{2000}-\frac{4}{2000}+\frac{x}{2001}-\frac{3}{2001}+\frac{x}{2002}-\frac{2}{2002}=\frac{x}{2}-\frac{2002}{2}+\frac{x}{3}-\frac{2001\\}{3}+\frac{x}{4}-\frac{2000}{4}\)

\(\Leftrightarrow\frac{x}{2000}-\frac{1}{500}+\frac{x}{2001}-\frac{1}{667}+\frac{x}{2002}-\frac{1}{1001}-\frac{x}{2}-\frac{x}{3}-\frac{x}{4}+1001+667+500=0\)

\(\Leftrightarrow\left(\frac{x}{2000}+\frac{x}{2001}+\frac{x}{2002}-\frac{x}{2}-\frac{x}{3}-\frac{x}{4}\right)+\left(1001+667+500-\frac{1}{500}-\frac{1}{667}-\frac{1}{1001}\right)=0\)

=> x=1

8 tháng 8 2018

\(\dfrac{x+1}{2953}+\dfrac{x+953}{2001}>-2\)

\(\Leftrightarrow\dfrac{x+1}{2953}+1+\dfrac{x+953}{2001}+1>-2+1+1\)

\(\Leftrightarrow\dfrac{x+2954}{2953}+\dfrac{x+2955}{2001}>0\)

\(\Leftrightarrow\left(x+2954\right)\left(\dfrac{1}{2953}+\dfrac{1}{2001}\right)>0\)

\(\Leftrightarrow x+2954>0\\ \Leftrightarrow x>-2954\)

Vậy.......