解方程5^2=45x

5^2 = 45x
25 = 45x
x = 25/45
x = 5/9

2013-11-13 08:15:33 補充：
可能條題目係咁：

5^(2x) = 4(5^x)
(5^x)^2 = 4(5^x)
(5^x)^2 - 4(5^x) = 0
(5^x)[(5^x) - 4] = 0
5^x = 0 or 5^x = 4
x(log 5) = log 0 or x(log 5) = log 4
x = 1 or x = log 4 / log 5

5^2=45x
25=45x
X=25/45=5/9

我想問你
5^2x 點轉做 (5^x)^2?
5^2x = 5 ^ (x+x)吧? 而 (5^x)^2 = 5 ^ (x^2) 吧?

http://hk.knowledge.yahoo.com/question/question?qid=7013111200197

這個不需解，兩面除以45，就得到5/9。