題目如下：
if |z| < = 1
which of the following statements must be true:
Indicate all such statements
A.Z^2 <= 1
B. z^2 <= z
C. Z^3 <= z
另一題：
n=positive interger, x= 7n+2, y=6n+3
QA: The ones digit of x+y
QB: 5
比較Ａ和Ｂ大小
感謝大家