\(3.3^x+5.3^{x+1}=16\)
\(\Leftrightarrow3^{x+1}+5.3^{x+1}=16\)
\(\Leftrightarrow3^{x+1}.\left(1+5\right)=16\)
\(\Leftrightarrow3^{x+1}.6=16\)
\(\Leftrightarrow3^{x+1}=\frac{8}{3}\)
\(\Leftrightarrow3^{x+1}=3^{-0,107210739+1}\)
\(\Leftrightarrow x=-0,107.........\)
Đề sai m3 r` bn