【题中(X-Z)少了平方,否则当X=3/2、Y=3/4、Z=3/8时满足题意,但ABCD都不成立】

令 X-Y = a ,Y-Z = b ,
则 X-Z = (X-Y)+(Y-Z) = a+b ；
已知,(X-Z)²-4(X-Y)(Y-Z) = 0 ,
即有：(a+b)²-4ab = 0 ,
则有：(a-b)² = (a+b)²-4ab = 0 ,
可得：a-b = 0 ,
即有：(X-Y)-(Y-Z) = 0 ,
所以,Z+X-2Y = 0 ,
选 D .
希望能解决您的问题.