10（x+2）^2-29(x+2)+10
=(5x+10-2)(2x+2-5)
=(5x+8)(2x-3)
(x+1)(x+2)(x+3)(x+4)+1
=(x^2+5x+1)^2
(y^2-1)(y+3)(y+5)-9
=(y+1)(y-1)(y+3)(y+5)-9
=(y^2+4y+3)(y^2+4y-5)-9
=(y^2+4y-5)^2+8(y^+4y-5)-9
=(y^2+4y+4)(y^+4y-6)
=(y+2)^2(y^+4y-6)
a^3·9x+0.6ay+x+2y=?
7m^2-3n+mn-21m
=7m(m-3)+n(m-3)
=(m-3)(7m+n)