Question

[Tạ Thị Hồng]

câu hỏi hơn dài :( xin lỗi 

Answer 1

[Nguyễn Lê Phước Thịnh]

f: \(\Leftrightarrow\left[{}\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)

i: \(\Leftrightarrow2\cdot3^x=54\)

hay x=3

Answer 2

[Nguyễn Hoàng Minh]

\(f,\Rightarrow\left[{}\begin{matrix}x-2=4\\2-x=4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\\ j,\Rightarrow3^x=\dfrac{49+5}{2}=27\\ \Rightarrow x=3\\ k,\Rightarrow7x=2^3+3^3=35\Rightarrow x=5\\ l,\Rightarrow x-1=1\Rightarrow x=2\\ m,\Rightarrow3^{x+3}=3^9:3^4=3^5\\ \Rightarrow x=2\\ n,\Rightarrow30-2x=\left(150-42\right)\cdot3=324\\ \Rightarrow2x=-294\\ \Rightarrow x=-147\\ o,\Rightarrow x-15=2\cdot5=10\\ \Rightarrow x=25\\ p,\Rightarrow225-x+10=\dfrac{125}{5}=25\\ \Rightarrow x=210\)