因式分解；1/2x^2+xy+1/2y^2

(x-y)^2-(xy+1)因式分解 y^3+xy^2+2xy+x^2-1 因式分解 因式分解xy²-2xy+x+2y-1 因式分解 x(x-1)+y(y+1)-2xy 因式分解:X(X-1)+Y(Y+1)-2XY （x+y）(x-1)-xy-y^2 怎么因式分解? 因式分解 x方+y方-xy+2x-y+1 (xy-1)^2+(x+y-z)(x+y-zxy)因式分解 xy(xy+1)+xy+3-2(x+y+1/2)-(x+y-1)^2因式分解 因式分解（x+y)(x+y+2xy)+(xy+1)(xy-1) X^2（X+1）-Y（XY+X）因式分解 因式分解x^2y^2+x^2y+xy^2+3xy+x+y+1 x^2-y^2-1+2y因式分解,-x^2-y^2+1-2xy因式分解 2x²-xy+3x-y+1因式分解 因式分解（x+y-2xy)(x+y-2)+(xy-1)^2设x+y=a,xy=b, 因式分解；1/2x^2+xy+1/2y^2 因式分解：（x^2-y^2)^2-(1+2xy)^2 因式分解(1+2xy)^2-(x^2+y^2)^2