Question

把x?2y222y?x中根号外的因式移入根号内是______

把x?2y222y?x中根号外的因式移入根号内是______．

Answer 1

∵

2

2y?x

＞0，
∴

x?2y

2

=-

2

2y?x

＜0，
∴

x?2y

2

2 2y?x

=-

( x?2y 2 )2× 2 2y?x

=-

2y?x 2

．
故答案是：-

2y?x 2

．