toán so hot đêy

T

thaonguyenkmhd

$\dfrac{x}{6} - \dfrac{1}{y} = \dfrac{1}{2} \rightarrow \dfrac{xy}{6y} - \dfrac{6}{6y} = \dfrac{6y}{12y} \rightarrow xy-6=6y \rightarrow xy-6y=6 \rightarrow y(x-6)=6$

Do $ x, y \in Z \rightarrow y; \ x-6 \in Ư(6) $

Từ đây lập bảng là ra
 
S

soicon_boy_9x

$\dfrac{x}{6}-\dfrac{1}{y}=\dfrac{1}{2}$
$\rightarrow \dfrac{1}{y}=\dfrac{x}{6}-\dfrac{1}{2}$
$\rightarrow \dfrac{1}{y}=\dfrac{x-3}{6}$
$\rightarrow (x-3)y=6$
$\rightarrow y\in \{1;2;3;6;-1;-2;-3;-6 \}$
$\rightarrow x-3 \in \{ -6;-3;-2;-1;6;3;2;1 \}$
$\rightarrow x\in \{-3;0;1;2;9;6;5;4 \}$
P/S:Mình sửa cho bạn thaonguyenkmhd 1 chút là:
$\dfrac{x}{6} - \dfrac{1}{y} = \dfrac{1}{2} \rightarrow \dfrac{2xy}{12y} - \dfrac{12}{12y} = \dfrac{6y}{12y} \rightarrow 2xy-12=6y \rightarrow 2xy-6y=12 \rightarrow y(2x-6)=12$
 
H

harrypham

Another SOLUTION: $$\dfrac{x}{6}- \dfrac{1}{y}= \dfrac{1}{2} \iff \dfrac 1y= \dfrac{x}{6}- \dfrac 36$$ $$\iff \dfrac 1y = \dfrac{x-3}{6} \iff y(x-3)=6$$
 
You must log in or register to reply here.
Top Bottom