(Áp dụng t/c của dãy tỉ số bằng nhau)

1/2x=3y=4z và x-y-z=35

2/\(\dfrac{x}{3}\)=\(\dfrac{y}{4}\):\(\dfrac{y}{5}\)=\(\dfrac{z}{7}\)và 2x+3y-z=186

\(\dfrac{1}{2}\)x=\(\dfrac{2}{3}\)y=\(\dfrac{3}{4}\)z và x-y=15 (Áp dụng t/c của dãy tỉ số bằng nhau)

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