第 2 題
x = a + b，其中 a 為整數，0 ≦ b < 1
[x] = a，{x} = b
ab = (a + b)2 / 8
b = 3a ± (2√2)a
0 ≦ 3a ± (2√2)a < 1
......

第 1 題
應該從 a 下手比較快
8 * 8 > 60，故 a 最大是 7
a = 7，b = 7 ~ 8
a = 6，b = 6 ~ 10
a = 5，b = 5 ~ 12
a = 4，b = 4 ~ 15
a = 3，b = 3 ~ 20
a = 2，b = 2 ~ 30
a = 1，b = 1 ~ 60