a.
Ta có:
\(\left|2x-7\right|=1\dfrac{1}{2}-\dfrac{1}{2}\\ \left|2x-7\right|=\dfrac{3}{2}-\dfrac{1}{2}\\ \left|2x-7\right|=1\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-7=1\\2x-7=-1\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}2x=8\\2x=6\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=4\\x=3\end{matrix}\right.\)
b.
\(\Leftrightarrow3^n\left(3^{-1}+4\right)=13.3^5\)
\(\Rightarrow3^n=3^6\)
\(\Rightarrow n=6\)
Đúng 2
Bình luận (0)
