\(4^{x+3}-3.4^{x+1}=13.4^{11}\)
\(\Leftrightarrow4^x.\left(4^3-3.4\right)=13.4^{11}\)
\(\Leftrightarrow4^x.52=13.4^{11}\)
\(\Leftrightarrow\frac{4^x.52}{13}=\frac{13.4^{11}}{13}\)
\(\Leftrightarrow4^x.4=4^{11}\)
\(\Leftrightarrow4^{x+1}=4^{11}\)
\(\Leftrightarrow x+1=11\)
\(\Leftrightarrow x=10\)
Vậy : \(x=10\)
4x+3-3.4x+1=13.411
4x.43-3.4x.4=13.411
4x(64-12)=13.411
4x.52=13.411
4x+1=411
x+1=11
x=10