Question

[Giang Ngọc Anh]

Tìm các cặp số nguyên (x;y) biết x/5 + 1/y-1 = 2/5

Giúp mk với

Answer 1

[nguyenthingoc]

\(\frac{x}{5}\) +\(\frac{1}{y-1}\) =\(\frac{2}{5}\)

⇒x(y-1) +5 = 2(y-1)

⇒(x-2)(y-1)=-5 = 1.(-5)=(-5).1

th1 \(\left\{{}\begin{matrix}x-2=1\\y-1=-5\end{matrix}\right.\) ⇒\(\left\{{}\begin{matrix}x=3\\y=-4\end{matrix}\right.\)

th2 \(\left\{{}\begin{matrix}x-2=-5\\y-1=1\end{matrix}\right.\)⇒\(\left\{{}\begin{matrix}x=-3\\y=2\end{matrix}\right.\)

vậy (x,y)=(3;-4),(-3;2)