1/2xy+y2+1+x2-1/2xy-2xy-1

1/2xy+y2+1+x2-1/2xy-2xy-1


什麼?



分解因式:x2-2xy+y2-6x+6y+9


=(x-y)2-6(x-y)+9
=(x-y-3)2



(2x2-y2)-[2y2-(x2+2xy)]=______.


3(X²;-y²;)+2xy