Question

Tìm các số nguyên x,y biết :x/4 =1/y +1/2

Answer 1

Ta có :\(\frac{1}{y}=\frac{x}{4}-\frac{1}{2}\Rightarrow\frac{1}{y}=\frac{x-2}{4}\)

\(\Rightarrow y\left(x-2\right)=4=4.1=\left(-4\right).\left(-1\right)=\left(-2\right).\left(-2\right)=2.2\)

Vì \(x,y\in Z\Rightarrow\left(x-2\right)\in Z\)

Ta có :

\(y=4;x-2=1\Rightarrow x=3;y=4\)

\(y=1;x-2=4\Rightarrow x=6;y=1\)

\(y=-1;x-2=-;\Rightarrow x=1;y=-4\)

\(y=-1;x-2=-4\Rightarrow x=-2;y=-1\)

\(y=-2;x-2=-2\Rightarrow x=0;y=-2\)

\(y=2;x-2=2\Rightarrow x=4;y=2\)