=10X^2-6XY-20XY+12Y^2
=10X^2-26XY+12Y^2
=(3X-3)*(X+4)-(2X+10)*(X-2)
=(3X^2+12X-3X-12)-(2X^2-4X+10X-20)
=(3X^2+9X-12)-(2X^2+6X-20)
=3X^2+9X-12-2X^2-6X+20
=X^2+3X+8
=10X^2-6XY-20XY+12Y^2
=10X^2-26XY+12Y^2
=(3X-3)*(X+4)-(2X+10)*(X-2)
=(3X^2+12X-3X-12)-(2X^2-4X+10X-20)
=(3X^2+9X-12)-(2X^2+6X-20)
=3X^2+9X-12-2X^2-6X+20
=X^2+3X+8