Lê Quốc Trần Anh Coordinator
03/08/2017 at 08:54-
Dao Trong Luan 03/08/2017 at 11:54
\(\Rightarrow\dfrac{x}{6}-\dfrac{1}{30}=\dfrac{2}{y}\)
\(\Rightarrow\dfrac{5x}{30}-\dfrac{1}{30}=\dfrac{2}{y}\)
\(\Rightarrow\dfrac{5x-1}{30}=\dfrac{2}{y}\)
\(\Rightarrow y\left(5x-1\right)=60\)
But \(5x-1\equiv4\left(mod5\right)\)
\(\Rightarrow5x-1\in\left\{-6;-1;4\right\}\)
If 5x - 1 = -6
=> 5x = -5 => x = -1
And y = 60 : -6 = -10
If 5x-1 = -1
=> 5x = 0 => x = 0
And y = 60 : -1 = -60
If 5x-1 = 4
=> 5x = 5 => x = 1
And y = 60 : 4 = 15
So \(\left(x,y\right)=\left(-1;-10\right);\left(0;-60\right);\left(1;15\right)\)
Lê Quốc Trần Anh selected this answer. -
baohong912006 04/08/2017 at 08:38
⇒x6−130=2y⇒x6−130=2y
⇒5x30−130=2y⇒5x30−130=2y
⇒5x−130=2y⇒5x−130=2y
⇒y(5x−1)=60⇒y(5x−1)=60
But 5x−1≡4(mod5)5x−1≡4(mod5)
⇒5x−1∈{−6;−1;4}⇒5x−1∈{−6;−1;4}
If 5x - 1 = -6
=> 5x = -5 => x = -1
And y = 60 : -6 = -10
If 5x-1 = -1
=> 5x = 0 => x = 0
And y = 60 : -1 = -60
If 5x-1 = 4
=> 5x = 5 => x = 1
And y = 60 : 4 = 15
So (x,y)=(−1;−10);(0;−60);(1;15