Jawabanmu

2014-01-18T17:14:51+07:00
[2/5^(x+2)]^3 =
2/5^(3x+6) = 25/4^21
2/5^(3x+6) = (5^2/2^2)^21
2/5^(3x+6) = [2/5^(-2)]^21
3x+6 = -42
3x = -48
x = -16