Question

Tìm số tự nhiên  x,y biết \(3\left(x+y\right)=xy\)

Answer 1

\(\Leftrightarrow\left(x-3\right)\left(y-3\right)=9\)

Answer 2

\(3\left(x+y\right)=xy\Rightarrow3x+3y=xy\Rightarrow3x-xy+3y=0\Rightarrow x\left(3-y\right)+3y-9=-9\Rightarrow x\left(3-y\right)+3\left(y-3\right)=-0\)

\(\left(x-3\right)\left(3-y\right)=-9\)

-9 = -1.9 = 1.-9 = -3.3 =  

(+) x - 3 = -1 va 3 - y = 9 => x = 2 va y = -6 

(+) tu lam voi tri thong minh cua ban