：(1).x^2-4y^2-x+2y
=(x+2y)(x-2y)-(x-2y)
=(x-2y)(x+2y-1)
(2).x^2-2x-b^2-2b
=x²-b²-2x-2b
=(x+b)(x-b)-2(x+b)
=(x+b)(x-b-2)
(3).5a^2 m+6abm-10a^2 n-12abn 最后一个m改成了n
=am(5a+6b)-2an(5a+6b)
=a(5a+6b)(m-2n)
(4)a(b-c)+a^2-bc
=ab+a²-ac-bc
=a(a+b)-c(a+b)
=(a+b)(a-c)
(5).x^2-y^2+2y-1
=x²-(y-1)²
=(x+y-1)(x-y+1)
（6）x^2+4y-1-4y^2
=x²-(2y-1)²
=(x+2y-1)(x-2y+1)