Question

\(\dfrac{x}{y}=\dfrac{5}{7}\) và \(x+y=-18\)

Answer 1

\(\dfrac{x}{y}=\dfrac{5}{7}\Rightarrow\dfrac{x}{5}=\dfrac{y}{7}\)

Áp dụng t/c dtsbn ta có:

\(\dfrac{x}{5}=\dfrac{y}{7}=\dfrac{x+y}{5+7}=\dfrac{-18}{12}=-\dfrac{3}{2}\)

\(\dfrac{x}{5}=-\dfrac{3}{2}\Rightarrow x=-\dfrac{15}{2}\\ \dfrac{y}{7}=-\dfrac{3}{2}\Rightarrow y=-\dfrac{21}{2}\)