Bài 2:
a: \(\dfrac{2}{3}+\dfrac{5}{3}x=\dfrac{5}{7}\)
\(\Leftrightarrow x\cdot\dfrac{5}{3}=\dfrac{1}{21}\)
hay \(x=\dfrac{1}{21}:\dfrac{5}{3}=\dfrac{1}{35}\)
b: \(\left(x+3\right)^2=25\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=5\\x+3=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-8\end{matrix}\right.\)

