单选题The symbol ☆ represents one of the fundamental arithmetic operators：+, -, ×, or ÷. If (x☆y)÷(y☆x)=1 for all positive values of x and y, then ☆ can represent ______.A+ onlyB÷onlyC+ or × onlyD- or × onlyE+, -, ×, ÷
单选题
The symbol ☆ represents one of the fundamental arithmetic operators：+, -, ×, or ÷. If (x☆y)÷(y☆x)=1 for all positive values of x and y, then ☆ can represent ______.
A
+ only
B
÷only
C
+ or × only
D
- or × only
E
+, -, ×, ÷
参考解析
解析：
(x × y)÷(y × x) = (xy)/(yx) = 1 and (x+y)÷(y+x)=(x+y)/(y+x)=1.
(x × y)÷(y × x) = (xy)/(yx) = 1 and (x+y)÷(y+x)=(x+y)/(y+x)=1.
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