No. 5≫ No.6 ≫No. 7
朱雀
2012/12/26 17:57
ヘルプ問題だけ
x3y-xy3-x2+y2+2xy-1
=x3y-xy3-x2+y2+2xy-1+x2y2-x2y2
=x2xy-xyy2-x2+y2+2xy-1+x2y2-x2y2
=x2(xy-1)-y2(xy-1)-x2y2+2xy-1+x2y2
=(x2-y2)(xy-1)-(xy-1)2+x2y2
=-(xy-1)2-(y2-x2)(xy-1)+y2x2
=-A2-(Y-X)A+YX
=-(A2+(Y-X)A+Y(-X))
=-(A+Y)(A-X)
=-(xy-1+y2)(xy-1-x2)
=(y2+xy-1)(x2-xy+1)
x3y-xy3-x2+y2+2xy-1
=x3y-xy3-x2+y2+2xy-1+x2y2-x2y2
=x2xy-xyy2-x2+y2+2xy-1+x2y2-x2y2
=x2(xy-1)-y2(xy-1)-x2y2+2xy-1+x2y2
=(x2-y2)(xy-1)-(xy-1)2+x2y2
=-(xy-1)2-(y2-x2)(xy-1)+y2x2
=-A2-(Y-X)A+YX
=-(A2+(Y-X)A+Y(-X))
=-(A+Y)(A-X)
=-(xy-1+y2)(xy-1-x2)
=(y2+xy-1)(x2-xy+1)