2（3a^2-b)-a(3b-4)
＝6a^2-2b-3ab+4a
=2a(3a+2)-b(3a+2)
=(2a-b)(3a+2)
2\
6x^3-7x^2+x
=x(6x^2+7x+1)
=x(6x+1)(x+1)