(1+5y)/5x = (1+7y)/4x = (1+5y-1-7y)/(5x-4x) = -2y/x
(1+5y)/5 = -2y
=> y = -1/15
Tìm được x = 2
\(\frac{\left(1+3y\right)}{12}=\frac{\left(1+5y\right)}{5x}=\frac{\left(1+7y\right)}{4x}\)
\(=\frac{\left(1+3y\right)}{5x}=\frac{\left(1+7y\right)}{4x}=\frac{\left(1+5y-1-7y\right)}{\left(5x-4x\right)}=\frac{-2y}{x}\)
\(\Rightarrow y=\frac{-1}{15}\)
\(\Rightarrow x=-2\)
(1+5y)/5x = (1+7y)/4x = (1+5y-1-7y)/(5x-4x) = -2y/x
(1+5y)/5 = -2y
tìm được y = -1/15
rồi tìm được x = 2
(1 + 3y)/12 = (1 + 5y)/5x = (1 + 7y)/4x