Helpppppppppppp!!!!!!

Đáp án:

$ x=4, y=3,z=\dfrac{5}{2}.$

Giải thích các bước giải:

$3x=4y \Rightarrow y=\dfrac{3}{4}x\\ 5y=6z \Rightarrow z=\dfrac{5}{6}y=\dfrac{5}{6}.\dfrac{3}{4}x=\dfrac{5}{8}x\\ xyz=30\\ \Leftrightarrow x.\dfrac{3}{4}x.\dfrac{5}{8}x=30\\ \Leftrightarrow \dfrac{15}{32}x^3=30\\ \Leftrightarrow x^3=64\\ \Leftrightarrow x=4\\ \Rightarrow y=\dfrac{3}{4}x=3\\ z=\dfrac{5}{8}x=\dfrac{5}{2}.$