设 lg2 = x ,则 10^x = 2 lg5 = y,则 10^y = 5因为：2×5 = 10即 10^x × 10^y = 10^(x+y) = 1010^(x+y) = 10 其实就是 (x + y) = 1 两边取对数 (x+y) = Lg10 所以：...