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8 tháng 7 2017

Giúp mình nhé các bạn mình đang cần gấp lắm

22 tháng 8 2016

D. Tìm x thuộc Z biết 

x+(x+1)+(x+2)+....+2016+2017=2017 

=> ( x + x + x + ..+ x ) + ( 1 + 2 + 3+...+2016 + 2017 ) = 2017 

<=> 2017x + 2035153 = 2017 

=> 2017x = -2033136

=> x = -1008

Vậy ...

23 tháng 8 2016

cảm ơn bạn nhưng bạn có biết những câu hỏi còn lại ko

12 tháng 7 2019

a) \(\frac{x}{x+1}=\frac{1}{2}\)

=> 2x = x + 1

=> 2x - x = 1

=> x = 1

b) \(\frac{x}{2}=\frac{x}{3}\)

=> 3x = 2x

=> 3x - 2x = 0

=> x = 0

c) \(\frac{x+1}{2}=\frac{x+1}{2017}\)

=> \(2017\left(x+1\right)=2\left(x+1\right)\)

=> 2017x + 2017 = 2x + 2

=> 2017x - 2x = 2 - 2017

=> 2015x = -2015

=> x = -2015 : 2015

=> x = -1

i) \(\frac{3}{x}=\frac{x}{2017}\)

=> x2 = 2017.3

=> x2 = 6051

=> \(\orbr{\begin{cases}x=\sqrt{6051}\\x=-\sqrt{6051}\end{cases}}\)

còn lại tự lm

\(a,\frac{x}{x+1}=\frac{1}{2}\)

\(\Rightarrow x=\frac{1}{2}.\left(x+1\right)\)

\(\Rightarrow x=\frac{1}{2}x+\frac{1}{2}\)

\(\Rightarrow x-\frac{1}{2}x=\frac{1}{2}\)

\(\Rightarrow\frac{1}{2}x=\frac{1}{2}\)

\(\Rightarrow x=1\)

\(b,\frac{x}{2}=\frac{x}{3}\)

\(\Rightarrow x=\frac{x}{3}.2\)

\(\Rightarrow x=\frac{2x}{3}\)

\(\Rightarrow3x=2x\)

\(\Rightarrow x=0\)

\(c,\frac{x+1}{2}=\frac{x+1}{2017}\)

\(\Rightarrow x+1=\frac{x+1}{2017}.2\)

\(\Rightarrow x+1=\frac{2x+2}{2017}\)

\(\Rightarrow2017x+2017=2x+2\)

\(\Rightarrow2017x-2x=2-2017\)

\(\Rightarrow2015x=-2015\)

\(\Rightarrow x=-1\)

\(i,\frac{3}{x}=\frac{x}{2017}\)

\(\Rightarrow x=3:\frac{x}{2017}\)

\(\Rightarrow x=\frac{6051}{x}\)

\(\Rightarrow x^2=6051\)

\(\Rightarrow x=\sqrt{6051}\)

\(o,\frac{x}{3}=\frac{x+1}{2}\)

\(\Rightarrow x=\frac{x+1}{2}.3\)

\(\Rightarrow x=\frac{3x+3}{2}\)

\(\Rightarrow2x=3x+3\)

\(\Rightarrow-x=3\)

\(\Rightarrow x=-3\)

\(m,\frac{x+1}{2}=\frac{x+2}{3}\)

\(\Rightarrow x+1=\frac{x+2}{3}.2\)

\(\Rightarrow x+1=\frac{2x+4}{3}\)

\(\Rightarrow3x+3=2x+4\)

\(\Rightarrow x=1\)

\(p,\frac{x+1}{2}=x\)

\(\Rightarrow2x=x+1\)

\(\Rightarrow x=1\)

\(m,\frac{2}{x}=\frac{x}{8}\)

\(\Rightarrow x=2:\frac{x}{8}\)

\(\Rightarrow x=\frac{16}{x}\)

\(\Rightarrow x^2=16\)

\(\Rightarrow x=4\)

\(Q,\frac{x^2}{2}=\frac{8}{x^2}\)

\(\Rightarrow x^2=\frac{8}{x^2}.2\)

\(\Rightarrow x^2=\frac{16}{x^2}\)

\(\Rightarrow x^4=16\)

\(\Rightarrow x=2\)

\(r,\frac{x^3}{2}=\frac{32}{x}\)

\(\Rightarrow x^3=\frac{32}{x}.2\)

\(\Rightarrow x^3=\frac{64}{x}\)

\(\Rightarrow x^4=64\)

\(\Rightarrow x=\sqrt[4]{64}\)

a: Sửa đề: \(\dfrac{2x-1}{11}+\dfrac{2x-2}{12}+\dfrac{2x-3}{13}=\dfrac{2x+5}{5}+\dfrac{2x+7}{3}+\dfrac{2x+4}{6}\)

\(\Leftrightarrow\dfrac{2x-1}{11}+1+\dfrac{2x-2}{12}+1+\dfrac{2x-3}{13}+1=\dfrac{2x+5}{5}+1+\dfrac{2x+7}{3}+1+\dfrac{2x+4}{6}+1\)

=>2x+10=0

hay x=-5

b: \(\dfrac{x-1}{2016}+\dfrac{x-2}{2015}+\dfrac{x-3}{2014}+\dfrac{x-4}{2013}+\dfrac{x-5}{2012}-5=0\)

\(\Leftrightarrow\left(\dfrac{x-1}{2016}-1\right)+\left(\dfrac{x-2}{2015}-1\right)+\left(\dfrac{x-3}{2014}-1\right)+\left(\dfrac{x-4}{2013}-1\right)+\left(\dfrac{x-5}{2012}-1\right)=0\)

=>x-2017=0

hay x=2017