1.（x+1）（x+2）-x-10
=x^2+2x+x+2-x-10
=x^2+2x-8
=(x-2)(x+4)
2.（x2-2x（x2-2x-4）+4
你把题写清楚
3.x2-3xy-18y2-3x-9y
=x^2-3xy-18y^2-3(x+3y)
=(x-6y)(x+3y)-3(x+3y)
(x+3y)(x-6y-3)