（x-1)(x-2)-3x(x+3)+2(x+2)(x-1),
=(x^2-3x+2)-(3x^2+9x)+2(x^2+x-2)
=x^2-3x+2-3x^2-9x+2x^2+2x-4
=-10x-2
=-10/3-2
=-16/3