) Tìm số nguyên x, y biết: a) 5x + 17 = 2 b) x-1/4=2/3.9/8 c) 3/x=y/28=-39/91

`a,` `5x+17=2`

`⇒5x=-15`

`⇒x=-3`

`b,` `x-1/4=2/3. 9/8`

`⇒x-1/4=3/4`

`⇒x=1`

`c,` `3/x=y/28=-39/91`

$\begin{cases}\dfrac{3}{x}=\dfrac{-39}{91}\\\dfrac{y}{28}=\dfrac{-39}{91}\end{cases}$

$⇒\begin{cases}x=-7\\y=-12\end{cases}$