化简(x-1)乘以根号下(x-1)分之负2
问题描述：
化简(x-1)乘以根号下(x-1)分之负2
答
(X-1)•√[(-2)/(X-1)]
=(X-1)•√[2/(1-X)] ----------------可知1-X>0.
=(X-1)•√[2(1-X)/(1-X)²]
=(X-1)•[√(2-2X)]/(1-X)}
= -√(2-2X).