Tìm x,y trong trường hợp sau: x/y=9/7; y/z=7/3 và x – y + 2 = -15 03/07/2021 Bởi Remi Tìm x,y trong trường hợp sau: x/y=9/7; y/z=7/3 và x – y + 2 = -15
$\dfrac{x}{y}=\dfrac{9}{7}\Leftrightarrow \dfrac{x}{9}=\dfrac{y}{7}$ $\dfrac{y}{z}=\dfrac{7}{3}\Leftrightarrow \dfrac{y}{7}=\dfrac{z}{3}$ $\Rightarrow \dfrac{x}{9}=\dfrac{y}{7}=\dfrac{z}{3}$ $=\dfrac{x-y+z}{9-7+3}=\dfrac{-15}{5}=-3$ $\to x=-3.9=-27; y=-3.7=-21; z=-3.3=-9$ Bình luận
$\dfrac{x}{y}=\dfrac{9}{7}\Leftrightarrow \dfrac{x}{9}=\dfrac{y}{7}$
$\dfrac{y}{z}=\dfrac{7}{3}\Leftrightarrow \dfrac{y}{7}=\dfrac{z}{3}$
$\Rightarrow \dfrac{x}{9}=\dfrac{y}{7}=\dfrac{z}{3}$
$=\dfrac{x-y+z}{9-7+3}=\dfrac{-15}{5}=-3$
$\to x=-3.9=-27; y=-3.7=-21; z=-3.3=-9$