gwd-5-13

goodfishs

Q13:

What is the value of the integer n?

(1) n(n + 2) = 15

(2) (n + 2)ⁿ = 125

The right answer is B but why not D?

From (1) we can get 1,3,5,15 are the facters of 15. But only when n=3, n(n+2)=15 is valid.

From (2) we can get 125 = 5^3, so n=3, (n+2)^n is valid.

goodfishs

thanks @!!!!!!!!!!!

leadership

假设

Q13: What is the value of the integer n? （没有提到是整数） (1) n(n + 2) = 15 (2) (n + 2)n = 125 那么结果还是B吗，除了3，还有别的数（不论整数分数）能够满足 (n + 2)n = 125 吗，

我认为没有了，不知大家有没有别的想法

欢迎讨论

ghfgss231

选项（1）中，n还可以等于-5，也可以等于3，所以两个解，不能确定.