Question

Tìm x ; y :

2x² + 2y² - 2xy + 2x + 2y + 2 = 0

Bài 2 :

\(\frac{\left(n+2\right)!}{\left(n-1\right)!}\) = ?

Answer 1

\(\left(x^2+y^2-2xy\right)+\left(x^2+2x+1\right)+\left(y^2+2y+1\right)=0\)

=> x=y=-1

Bài 2: n(n+1)(n+2)

Answer 2

\(2x^2+2y^2-2xy+2x+2y+2=0\)

\(\left(x^2+2xy+y^2\right)+\left(x^2+2x+1\right)+\left(y^2+2y+1\right)=0\)