Giải thích các bước giải:
Ta có:
$\dfrac{bz-cy}{a}=\dfrac{cx-az}{b}=\dfrac{ay-bx}{c}$
$\to \dfrac{bxz-cxy}{ax}=\dfrac{cxy-ayz}{by}=\dfrac{ayz-bzx}{cz}=\dfrac{bxz-cxy+cxy-ayz+ayz-bzx}{ax+by+cz}=\dfrac0{ax+by+xz}=0$
$\to bxz-cxy=cxy-ayz=ayz-bzx=0$
$\to ayz=bxz=cxy$
$\to\dfrac{ayz}{xyz}=\dfrac{bxz}{xyz}=\dfrac{cxy}{xyz}$
$\to \dfrac{a}x=\dfrac{b}y=\dfrac{c}z$
$\to \dfrac{x}{a}=\dfrac{y}{b}=\dfrac{z}{c}$