Math World No.010

最近沒在解不等式了......
改成解代數的問題了～ (那不是差不多嗎 XD)
二、三題的答案花一些時間容易湊出來～
不過不能省略證明唷～ ^^

1.
Find the least positive integer m such that
(C 2n取n)^(1/n)<m
for all positive integers n.

2.
Find all real numbers x for which
10^x + 11^x + 12^x = 13^x + 14^x

3.
Find all real numbers x for which
2^x + 3^x - 4^x + 6^x - 9^x = 0