a^2-2ab+b^2+2(a-b)+1=0
(a-b)^2+2(a-b)+1=0
(a-b+1)^2=0
a-b+1=0
a-b=-1
4a^4±4a^2+1=(2a^2±1)^2
5x^2-45y^2
=5(x^2-9y^2)
=5(x+3y)(x-3y)
25x^3+10x^2y+xy^2
=x(25x^2+10xy+y^2)
=x(5x+y)^2
x^5-xy^4
=x(x^4-y^4)
=x(x^2-y^2)(x^2+y^2)
=x(x-y)(x+y)(x^2+y^2)
a(a-1)-(a^2-b）=3,求a^2+b^2-2ab的值
a(a-1)-(a^2-b）=3
a^2-a-a^2+b=3
b-a=3
a^2+b^2-2ab
=(a-b)^2
=( b-a)^2
=3^2
=9