a)
\(2^x+2^{x+3}=788\)
\(2^x\left(1+2^3\right)=788\)
\(2^x.\left(1+8\right)=788\)
\(2^x.9=788\)
\(2^x=788:9\)
2^x = 87,(5)
Số dài quá, tự bấm máy tính đi
b) \(\left(5x-1\right)^3=-27\)
\(\left(5x-1\right)^3=\left(-3\right)^3\)
\(\Rightarrow5x-1=-3\)
5x = -3 + 1
5x = -2
x = -2/5