(3x^2-2x+1)·3x
=3x^2-5x+1
（6a^3b^2-9a^2b+3ab）÷3ab
=2a^2b-3a+1
(2m+3)^2-3m(m-2)-(m+2)(m-2)
=(4m^2+12m+9)-(3m^2-6)-(m^2-4)
=4m^2+12m+9-3m^2+6-m^2+4
=4m^2-3m^2-m^2+12m+9+6+4
=12m+19
[(3x-2)^2-(2x+1)(2x-1)]·3x
=[(9x^2-12x+4)-(4x^2-1)]3x
=(9x^2-12x+4-4x^2+1)3x
=(9x^2-4x^2-12x+4+1)3x
=(5x^2-12x+5)3x
=15x^3-36x^2+15x