giúp mìk vs : c/m: (x^2011+x^2010+....+x+1) chia hết (x^502+x^501+...+x+1)
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Chào mai xinh đẹp
1<=>( x-4)/2009 -1 +( x-3)/2010-1 -(x-2)/2011-1-(x-1)/2012-1=0
<=> (x-2013)/2009+ (x-2013)/2010-(x-2013)/2011-(x-2013)/2012=0
<=> (x-2013)( 1/2009+1/2010-1/2011-1/2012)=0
=> x-2013=0=> x=2013
pp mai
a: \(=\dfrac{499}{500}\cdot\dfrac{500}{501}\cdot\dfrac{501}{502}\cdot\dfrac{502}{503}=\dfrac{499}{503}\)
b: =6,5(3,25+4,75+8)=6,5*16=104
a) \(\frac{x+4}{x+3}< 1\)
\(\Leftrightarrow\frac{x+4}{x+3}-1< 0\)
\(\Leftrightarrow\frac{x+4-x-3}{x+3}< 0\)
\(\Leftrightarrow\frac{1}{x+3}< 0\)
\(\Leftrightarrow x+3< 0\)
\(\Leftrightarrow x< -3\)
Vậy \(x< -3\)
b) \(\frac{x+3}{x+4}>1\)
\(\Leftrightarrow\frac{x+3}{x+4}-1>0\)
\(\Leftrightarrow\frac{x+3-x-4}{x+4}>0\)
\(\Leftrightarrow-\frac{1}{x+4}>0\)
\(\Leftrightarrow x+4< 0\)
\(\Leftrightarrow x< -4\)
Vậy \(x< -4\)
c) \(\frac{x+3}{2010}+\frac{x+2}{2011}+\frac{x+1}{2012}+\frac{x+2025}{4}=0\)
\(\Leftrightarrow\left(\frac{x+3}{2010}+1\right)+\left(\frac{x+2}{2011}+1\right)+\left(\frac{x+1}{2012}+1\right)+\left(\frac{x+2025}{4}-3\right)=0\)
\(\Leftrightarrow\frac{x+2013}{2010}+\frac{x+2013}{2011}+\frac{x+2013}{2012}+\frac{x+2013}{4}=0\)
\(\Leftrightarrow\left(x+2013\right)\left(\frac{1}{2010}+\frac{1}{2011}+\frac{1}{2012}+\frac{1}{4}\right)=0\)
\(\Leftrightarrow x+2013=0\) (Vì \(\frac{1}{2010}+\frac{1}{2011}+\frac{1}{2012}+\frac{1}{4}\ne0\))
\(\Leftrightarrow x=-2013\)
Vậy \(x=-2013\)
Nhớ tick đó ✔✔✔
Bài 1 :
72x+3 . 75-2x : 7x + 7x = 1
- > 7(2x+3)+(5-2x)-7 + 7x = 1
- > 71 + 7x = 1
- > 7x = 1 - 7 = -6 - > x thuộc rỗng
Từ \(\frac{y+z-x}{x}=\frac{z+x-y}{y}=\frac{x+y-z}{z}\)
\(\Rightarrow\frac{y+z-x}{x}+2=\frac{z+x-y}{y}+2=\frac{x+y-z}{z}+2\)
\(\Rightarrow\frac{x+y+z}{x}=\frac{x+y+z}{y}=\frac{x+y+z}{z}\left(1\right)\)
*)Xét \(x+y+z\ne0\left(2\right)\). Từ (1) và (2)
\(\Rightarrow x=y=z\). Khi đó \(B=\frac{x+y}{y}\cdot\frac{y+z}{z}\cdot\frac{x+z}{x}=2\cdot2\cdot2=8\)
*)Xét \(x+y+z=0\)\(\Rightarrow\left\{\begin{matrix}x+y=-z\\y+z=-x\\x+z=-y\end{matrix}\right.\)
Khi đó \(B=\frac{x+y}{y}\cdot\frac{y+z}{z}\cdot\frac{x+z}{x}=\frac{-z}{y}\cdot\frac{-x}{z}\cdot\frac{-y}{x}=-1\)
a)
Ta có \(\frac{y+z-x}{x}=\frac{z+x-y}{y}=\frac{x+y-z}{z}\)
Áp dụng tính chất dãy tỉ số bằng nhau ta có
\(\frac{y+z-x}{x}=\frac{z+x-y}{y}=\frac{x+y-z}{z}=\frac{y+z-x+z+x-y+x+y-z}{x+y+z}=\frac{x+y+z}{x+y+z}=1\)
\(\Rightarrow\left\{\begin{matrix}\frac{y+z-x}{x}=1\\\frac{z+x-y}{y}=1\\\frac{x+y-z}{z}=1\end{matrix}\right.\)
\(\Rightarrow\left\{\begin{matrix}y+z-x=x\\z+x-y=y\\x+y-z=z\end{matrix}\right.\)
\(\Rightarrow\left\{\begin{matrix}y+z=2x\\z+x=2y\\x+y=2z\end{matrix}\right.\) (1)
Ta có \(B=\left(1+\frac{x}{y}\right)\left(1+\frac{y}{z}\right)\left(1+\frac{z}{x}\right)\)
\(\Rightarrow B=\frac{x+y}{y}.\frac{y+z}{z}.\frac{x+z}{x}\)
Thế (1) vào biểu thức B
\(\Rightarrow B=\frac{2z}{y}.\frac{2x}{z}.\frac{2y}{x}\)
\(\Rightarrow B=2.2.2=8\)
Vậy biểu thức \(B=8\)
Ta có: \(x-5⋮x-1\)
=> \(\left(x-1\right)-4⋮x-1\)
=> \(-4⋮x-1\)
Vì \(x\in Z\Rightarrow x-1\inƯ\left(-4\right)=\left\{\pm1;\pm2;\pm4\right\}\)
Ta có bảng sau:
x-1 | 1 | -1 | 2 | -2 | 4 | -4 |
x | 2 | 0 | 3 | -1 | 5 | -3 |
Vậy \(x\in\left\{2;0;3;-1;5;-3\right\}\)