Ta có :

\(\frac{3x-2y}{4}=\frac{2z-4x}{3}=\frac{4y-3z}{2}\)

suy ra : \(\frac{4.\left(3x-2y\right)}{16}=\frac{3.\left(2z-4x\right)}{9}=\frac{2.\left(4y-3z\right)}{4}\)

\(=\frac{12x-8y+6z-12x+8y-6z}{29}=0\)

Vậy \(\frac{3x-2y}{4}=0\Rightarrow3x=2y\Rightarrow\frac{x}{2}=\frac{y}{3}\)( 1 )

\(\frac{2z-4x}{3}=0\Rightarrow2z=4x\Rightarrow\frac{x}{2}=\frac{z}{4}\)( 2 )

Từ ( 1 ) và ( 2 ) ta được : \(\frac{x}{2}=\frac{y}{3}=\frac{z}{4}\)

\(\frac{3x-2y}{4}=\frac{2z-4x}{3}=\frac{4y-3z}{2}=\frac{3xz-2yz}{4z}=\frac{2yz-4xy}{3y}=\frac{4xy-3xz}{2x}=\frac{\left(3xz-2yz\right)+\left(2yz-4xy\right)+\left(4xy-3xz\right)}{4z+3y+2x}=0\)

\(\Rightarrow\hept{\begin{cases}3x-2y=0\\2z-4x=0\end{cases}}\Rightarrow\hept{\begin{cases}3x=2y\\2z=4x\end{cases}}\Rightarrow\hept{\begin{cases}\frac{x}{2}=\frac{y}{3}\\\frac{x}{2}=\frac{z}{4}\end{cases}\Rightarrow\frac{x}{2}=\frac{y}{3}=\frac{z}{4}}\)

vì sao bằng 0 thế

ndo81 chi ko

\(\frac{3x-2y}{4}=\frac{2z-4x}{3}=\frac{4y-3z}{2}\)

\(\Rightarrow\frac{3xz-2yz}{4z}=\frac{2yz-4xy}{3y}=\frac{4xy-3xz}{2x}\)

Áp dụng tính chất của dãy tỉ số bằng nhau, ta có :

\(\frac{3xz-2yz}{4z}=\frac{2yz-4xy}{3y}=\frac{4xy-3xz}{2x}=\frac{\left(3xz-2yz\right)+\left(2yz-4xy\right)+\left(4xy-3xz\right)}{4z+3y+2x}=0\)

\(\Rightarrow3x-2y=0\Rightarrow3x=2y\Rightarrow\frac{x}{2}=\frac{y}{3}\left(1\right)\)

\(\Rightarrow4y-3z=0\Rightarrow4y=3z\Rightarrow\frac{y}{3}=\frac{z}{4}\left(2\right)\)

Từ ( 1 ) và ( 2 ) \(\Rightarrow\frac{x}{2}=\frac{y}{3}=\frac{z}{4}\)

what  t f***********

\(\frac{3x-2y}{4}=\frac{2z-4x}{3}=\frac{4y-3z}{2}\)

\(\Rightarrow\frac{3xz-2yz}{4z}=\frac{2zy-4xy}{3y}=\frac{4yx-3zx}{2x}\)

\(\Rightarrow\frac{3xz-2yz+2zy-4xy+4yx-3zx}{4z+3y+2x}\)\(=\frac{0}{4z+3y+2x}=0\)

\(\Rightarrow3x-2y=0\Rightarrow3x=2y\Rightarrow\frac{x}{2}=\frac{y}{3}\left(1\right)\)

\(\Rightarrow2z-4x=0\Rightarrow2z=4x\Rightarrow\frac{x}{2}=\frac{z}{4}\left(2\right)\)

\(Từ\left(1\right),\left(2\right)\Rightarrow\frac{x}{2}=\frac{y}{3}=\frac{z}{4}\left(đpcm\right)\)

\(\frac{3x-2y}{4}=\frac{2z-4x}{3}=\frac{4y-3z}{2}\)

\(=\frac{12x-8y}{4^2}=\frac{6z-12x}{3^2}=\frac{8y-6z}{2^2}\)

\(=\frac{12x-8y+6z-12x+8y-6z}{4^2+3^3+2^2}\)

\(=\frac{\left(12x-12x\right)-\left(8y-8y\right)+\left(6z-6z\right)}{16+9+4}\)

\(=\frac{0-0-0}{16+9+4}=0\)

\(\Rightarrow\hept{\begin{cases}3x-2y=0\\2z-4x=0\\4y-3z=0\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}\frac{x}{2}=\frac{y}{3}\\\frac{z}{4}=\frac{x}{2}\\\frac{y}{3}=\frac{z}{4}\end{cases}\Rightarrow\frac{x}{2}=\frac{y}{3}=\frac{z}{4}}\)

Ta có :

\(\frac{3x-2y}{4}=\frac{2z-4x}{3}=\frac{4y-3z}{2}\)

\(\Rightarrow\frac{3xz-2y}{4z}=\frac{2yz-4xy}{3y}=\frac{4xy-3xz}{2x}\)

\(\Rightarrow\frac{\left(3xz-2y\right)+\left(2yz-4xy\right)+\left(4xy-3xz\right)}{4z+3y+2x}=0\)

\(\Rightarrow\hept{\begin{cases}3x-2y=0\\2z-4x=0\end{cases}\Rightarrow\hept{\begin{cases}3x=2y\\2z=4x\end{cases}}}\)

\(\Rightarrow\hept{\begin{cases}\frac{x}{2}=\frac{y}{3}\\\frac{x}{2}=\frac{z}{4}\end{cases}\Leftrightarrow\frac{x}{2}=\frac{y}{3}=\frac{z}{4}\left(đpcm\right)}\)