3x^2-8x+2x^2-13x^2+2x-2x^3+3
=3x^2+2x^2-13x^2-2x^3-8x+2x+3
=-8x^2-2x^3-6x+3
=-8*(-3/2)^2-2*(-3/2)^3-6*(-3/2)+3
=-8*9/4+2*27/8+9+3
=-18+27/4+12
=-6+27/4
=-6+6+3/4
=3/4