2 pangkat 4x+1 + 5 (4 pangkat x) = 3 x = ?

[tex]2^{4x+1}+5.4^{x}=3 \\ 4.2^{4x}+5.4^{x}=3 \\ 4.4^{2x}+5.4^{x}=3 \\ $Misal, $4^{x}=p \\ 4p^2+5p=3 \\ 4p^2+5p-3=0 \\ (2p+3)(2p-1)=0 \\ p=-\frac{3}{2}$ (Tidak memenuhi)$ \\ p=\frac{1}{2} \\ 4^{x}=\frac{1}{2} \\ x=^4\log\frac{1}{2} \\ x=-\frac{1}{2}[/tex]