如何確定兩對數字相等

Question

我有兩對數字。讓我們說我有（A，B）和（X，Y） 問題是：

if 
A-B = X-Y and 
A+B = X+Y and 
A/B = X/Y and 
A*B = X*Y 

我可以斷定A = X和B = Y？

Answer 1

我相信是這樣：

A-B = X-Y so 
A = X-Y+B and 
B = -X+Y+A so if 
A+B=X+Y then 
A-X+Y+A=X+Y becomes 
2A=2X or A=X 
and if 
A+B=X+Y then 
X-Y+B+B=X+Y becomes 
2B=2Y or B=Y 

Answer 2

這取決於號碼類型。對於float，您不能得出結論A = X和B = Y。

假設A = 1; B = Positive Infinity; X = 2; Y = Positive Infinity;

然後A-B = X-Y = Negative Infinity;A+B = X+Y = Positive Infinity;A/B = X/Y = 0;A*B = X*Y = Positive Infinity;