兩道因式分解題(初二) (1)xy(a^+1)+a(x^+y^) (2)xya^-(xz-y^)a-xy (3)ab(x^+y^)+xy(a^+b^)

兩道因式分解題(初二) (1)xy(a^+1)+a(x^+y^) (2)xya^-(xz-y^)a-xy (3)ab(x^+y^)+xy(a^+b^)


(1)=a^xy+xy+ax^+ay^
=ax(ay+x)=y(ay+x)
=(ay+x)(ax+y)
(2)z應該是y吧
(3)=abx^+aby^+a^xy+b^xy
=ax(bx+ay)+by(ay+bx)
=(ax+by)(bx+ay)



1.(x+y)²;-10(x+y)+25
2.a²;b²;/4-ab+1


1、(X+Y-5)^2
2、(ab/2-1)^2



在實數範圍內因式分解(用公式法):x^2 +xy - 3y^2


x^2 +xy - 3y^2
=x^2 +xy+y^2/4- y^2/4- 3y^2
=(x+y/2)^2-13y^2/4
=(x+y/2-√13y/2)(x+y/2+√13y/2)