Question

tìm tổng 2 số x,y biết \(\frac{1+3y}{12}=\frac{1+5y}{5x}=\frac{1+7y}{4x}\)

Answer 1

\(\frac{1+3y}{12}=\frac{1+5y}{5x}=\frac{1+7y}{4x}\)

\(\Rightarrow\frac{1+3y}{12}=\frac{\left(1+5y\right)-\left(1+7y\right)}{5x-4x}\)

\(\Rightarrow\frac{1+3y}{12}=\frac{-2y}{x}\)

\(\Rightarrow\frac{1+3y}{12}=\frac{-10y}{5x}\)

\(\Rightarrow\frac{1+5y}{5x}=-\frac{10y}{5x}\)

\(\Rightarrow1+5y=-10y\)

\(\Rightarrow-15y=1\)

\(\Rightarrow y=\frac{1}{-15}\)