Ta có: x + y = 140 => x = 180 - y
Thay x = 180 - y vào x - x/8 = y + 8/x ta đc:
\(180-y-\frac{180-y}{8}=y+\frac{8}{180-y}\)
\(\Rightarrow\left(180-y\right)\left(180-y\right).8-\left(180-y\right)\left(180-y\right)=8y\left(180-y\right)+8.8\)
\(\Rightarrow\left(180-y\right)^2.8-\left(180-y\right)^2=8y\left(180-y\right)+64\)
\(\Rightarrow\left(32400-360y+y^2\right).8-\left(32400-360y+y^2\right)=1440y-8y^2+64\)
\(\Rightarrow259200-2880y+8y^2-32400+360y-y^2-1440y+8y^2-64=0\)
\(\Rightarrow15y^2-3960y+226736=0\)
\(\Rightarrow y=180\) hoặc y = 84
Khi y = 180 => x = 0
Khi y = 84 => x = 96
hình như tớ lm lộn rồi :v , thui kệ đi ..... mệt
