=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 ~ ~