a) \(x=\dfrac{7}{2}\)
b) \(\dfrac{1}{35}\)
c) \(\left[{}\begin{matrix}x=10\\x=-20\end{matrix}\right.\)
d) \(x=12.\)
Mấy bài này lần sau bạn tự tính nhé!
Bài 9 : Tìm x ,biết :
a) \(x+\dfrac{1}{2}=2^5:2^3\)
\(x+\dfrac{1}{2}=2^2\)
\(x+\dfrac{1}{2}=4\)
\(x=4-\dfrac{1}{2}\)
\(x=3\dfrac{1}{2}=\dfrac{7}{2}\)
b) \(\dfrac{2}{3}+\dfrac{5}{3}x=\dfrac{5}{7}\)
\(\dfrac{5}{3}x=\dfrac{5}{7}-\dfrac{2}{3}\)
\(\dfrac{5}{3}x=\dfrac{1}{21}\)
\(x=\dfrac{1}{21}:\dfrac{5}{3}\)
\(x=\dfrac{1}{35}\)
c) \(\left|x+5\right|-6=9\)
\(\left|x+5\right|=9+6\)
\(\left|x+5\right|=15\)
\(\Rightarrow\left[{}\begin{matrix}x+5=15\\x+5=-15\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=10\\x=-20\end{matrix}\right.\)
d) \(-\dfrac{12}{13}x-5=6\dfrac{1}{3}\)
\(-\dfrac{12}{13}x-5=\dfrac{79}{13}\)
\(-\dfrac{12}{13}x=\dfrac{79}{13}+5\)
\(-\dfrac{12}{13}x=\dfrac{144}{13}\)
\(x=\dfrac{144}{13}:\dfrac{-12}{13}\)
\(x=-12\)
