Bạn thử xem lại đề câu a nhé.
a) Ta có: \(2^{n+3}\cdot2^n=144\)
\(\Leftrightarrow2^n\cdot8\cdot2^n=144\)
\(\Leftrightarrow4^n=18\)
b) Ta có: \(\left(x-2015\right)^{x+2}-\left(x-2015\right)^{x+12}=0\)
\(\Leftrightarrow\left(x-2015\right)^x\cdot\left(x-2015\right)^2-\left(x-2015\right)^x\cdot\left(x-2015\right)^{12}=0\)
\(\Leftrightarrow\left(x-2015\right)^{x+2}\cdot\left[1-\left(x-2015\right)^{10}\right]=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2015=0\\x-2015=1\\x-2015=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2015\\x=2016\\x=2014\end{matrix}\right.\)
