3(4^x) = 250^x
(250^x) / (4^x) = 3
(250/4)^x = 3
62.5^x = 3
x = (ln(3) + 2*i*pi*n) / ln(62.5), for any integer n
x =~ 0.26567546278802995011819623353409 + 1.5194515676605343417262867213875*i*n, for any integer n
If x is a real number, then n = 0, so x = log[62.5](3) =~ 0.26567546278802995011819623353409
http://www.wolframalpha.com/input/?i=3%284^x%29%3D250^x
5^(x - 2) = 4^(2x + 3)
(5^x) / (5^2) = (4^(2x)) * (4^3)
(5^x) / 25 = (4^2)^x * 64
(5^x) = (16)^x * 64 * 25
(5^x) / (16^x) = 1600
(5/16)^x = 1600
0.3125^x = 1600
x = (ln(1600) + 2*i*pi*n) / ln(0.3125), for any integer n
x =~ -6.3429082850059839353806868350208 - 5.4018664254115702318363147656755*i*n, for any integer n
If x is a real number, then n = 0, so x = log[0.3125](1600) =~ -6.3429082850059839353806868350208
http://www.wolframalpha.com/input/?i=5^%28x+-+2%29+%3D+4^%282x+%2B+3%29