1) Cho \(\frac{3x-2y}{4}=\frac{2z-4x}{2}=\frac{4y-3z}{2}\) .
CMR: \(\frac{x}{2}=\frac{y}{3}=\frac{z}{4}\) .
2) Cho \(\frac{a}{b}=\frac{b}{c}=\frac{c}{d}=\frac{d}{a}\) ( với a+b+c+d \(\ne0\) .
Tính \(\frac{2a-b}{c+d}+\frac{2b-c}{d+a}+\frac{2c-d}{a+b}+\frac{2d-a}{b+c}\) .