下列各因式分解正确的是( )
A:x2+2x﹣1=(x﹣1)2
B:﹣x2+(﹣2)2=(x﹣2)(x+2)
C:x3﹣4x=x(x+2)(x﹣2)
D:(x+1)2=x2+2x+1
提示:1)Where did you go?
2)How did you go there?
3)Who did you go with?
4)How was the weather there?
5)What did you do there?
陕西榆林地区“乌金(煤)遍地”,资源非常丰富。5年前开始,该地“村村点火,处处冒烟”,被人们戏称为“黑三角”。据此回答下列各题。