a)\(\left(2x+\frac{3}{5}\right)^2-\frac{9}{25}=0\)
\(\Leftrightarrow\left(2x+\frac{3}{5}\right)^2-\left(\frac{3}{5}\right)^2=0\)
\(\Leftrightarrow\left(2x+\frac{3}{5}+\frac{3}{5}\right)\left(2x+\frac{3}{5}-\frac{3}{5}\right)=0\)
\(\Leftrightarrow\left(2x+\frac{6}{5}\right).2x=0\)
\(\Leftrightarrow\left[\begin{matrix}x=-\frac{3}{5}\\x=0\end{matrix}\right.\)
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b) \(3.\left(3x-\frac{1}{2}\right)^3+\frac{1}{19}=0\)
\(\Leftrightarrow\left(3x-\frac{1}{2}\right)^3=-\frac{1}{19}:3\)
\(\Leftrightarrow\left(3x-\frac{1}{2}\right)^3=-\frac{1}{57}\)
\(\Leftrightarrow3x-\frac{1}{2}=\sqrt[3]{-\frac{1}{57}}\)
\(\Leftrightarrow3x=\sqrt[3]{-\frac{1}{57}}+\frac{1}{2}\)
\(\Leftrightarrow x=\frac{\sqrt[3]{-\frac{1}{57}}+\frac{1}{2}}{3}\)
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