Question

tìm x,y,z biết 

 3x+y=x:y=x*y

Answer 1

Từ \(\frac{x}{y}=x.y\Rightarrow x=x.y.y=x.y^2\Rightarrow y^2=\frac{x}{x}=1\Rightarrow y\in\left\{-1;1\right\}\)

+)y=-1

Ta có:3x+(-1)=x.(-1) (vì \(3x+y=x.y\))

=>3x-1=-x=>3x-(-x)=1=>4x=1=>x=\(\frac{1}{4}\)

+)y=1

Ta có:3x+1=x.1

=>3x+1=x=>3x-x=1=>2x=1=>x=\(\frac{1}{2}\))

Vậy \(x\in\left\{\frac{1}{2};\frac{1}{4}\right\};y\in\left\{1;-1\right\}\)