4－4x＋x的2次方分支2x－6除以x加3括号乘以3－x分之x的平方＋x－6
=2(x-3)/(2-x)² ÷ (x+3) × (x-2)(x+3)/(3-x)
=-2/(x-2)
=-2/(-1/2 -2)
=4/5你确定确定