=x？ -2x？ +4x+3-(x？ +2x-6+x？ +2x-3)
=x？ -2x？ +4x+3-x？ -4x-x？ +9
=-3x？ + 12
=-3*(-2)? + 12
=- 12+ 12
=0
I hope it will help you, but I still hope to adopt it ~ ~