Let's do the long division #color(white)(aa)##4x^3-6x^2##color(white)(aaaaa)## +6##color(white)(aa)##∣#2x+3 #color(white)(aa)##4x^3+6x^2##color(white)(aaaaaaaaaa)##∣##2x^2-6x+9# #color(white)(aaa)##0-12x^2# #color(white)(aaaaa)##-12x^2-18x# #color(white)(aaaaaaaaa)##0+18x+6# #color(white)(aaaaaaaaaaa)##+18x+27# #color(white)(aaaaaaaaaaaaaaa)##0-21#