5^(x+2) + 5^(x+1) - 5^x < 3^(x/2+1) - 3^(x/2) - 3^(x/2-1).
5^x*(5^2+5-1) < 3^(x/2)*(3-1-(1/3)) 5^x*29 < 3^(x/2)*5/3 (5/sqrt(3))^x < 5/87 x < log_(5/sqrt(3))(5/87)