B=(2x+3)(4x^{2}-6x+9)-2(4x^{3}-1) A=(3x-5).(2x+11)-(2x+3).(3x+7) C=(x-1^{3})-(x+1^{3})+6(x+1).(x-1) :rongcon22:rongcon22:rongcon22:rongcon31:rongcon31:rongcon31