Question

giúp mình

1, tìm x

a, \(\dfrac{3}{5}\div x-\dfrac{1}{3}=\dfrac{4}{6}\)

b, \(\dfrac{x}{2}=\dfrac{-y}{4}=\dfrac{Z}{5}\) VÀ \(x-2y+3z=1200\)

Answer 1

a) \(\dfrac{3}{5}.\dfrac{1}{x}-\dfrac{1}{3}=\dfrac{4}{6}\)

\(\Leftrightarrow\dfrac{3}{5x}=1\)

\(\Leftrightarrow x=\dfrac{5}{3}\)

b) \(\dfrac{x}{2}=-\dfrac{2y}{8}=\dfrac{3z}{15}\)

áp dụng dãy tí số = nhau

\(\dfrac{x}{2}=-\dfrac{2y}{8}=\dfrac{3z}{15}=\dfrac{x-2y+3z}{2+8+15}=\dfrac{1200}{15}=80\)

\(\Leftrightarrow\dfrac{x}{2}=80\Rightarrow x=160\)

\(\Leftrightarrow-\dfrac{y}{4}=80\Rightarrow y=-320\)

\(\Leftrightarrow\dfrac{z}{5}=80\Rightarrow z=400\)