徐永強數學- p-set2-19

[邁向高等學府]

Does X+Y=XY?
1. x is neither a positive integer nor a negative integer
2. y is neither a positive integer nor a negative integer
答案為E
為什麼呢?

[汪汪北鼻]

1)insufficient
2)insufficient

1)2) x,y may be 0 or fraction
when x=y=0, x+y=xy=0
when x,y are fractions , the result is unpredictable

thus, the answer is E