Đáp án: `x = \frac{-7}{6}` hoặc `x = \frac{-11}{6}`
Giải thích các bước giải:
`( 2x + 3 )^2 = \frac{4}{9}`
`\Leftrightarrow ` \(\left[ \begin{array}{l}2x + 3 = \dfrac{2}{3}\\2x + 3 = -\dfrac{2}{3}\end{array} \right.\)
`\Leftrightarrow` \(\left[ \begin{array}{l}2x = \dfrac{2}{3} - 3\\2x = - \dfrac{2}{3} - 3 \end{array} \right.\)
`\Leftrightarrow` \(\left[ \begin{array}{l}2x = - \dfrac{7}{3}\\x=-\dfrac{11}{3}\end{array} \right.\)
`\Leftrightarrow` \(\left[ \begin{array}{l}x=- \dfrac{7}{3} : 2\\x=-\dfrac{11}{3} : 2 \end{array} \right.\)
`\Leftrightarrow` \(\left[ \begin{array}{l}x=- \dfrac{7}{6}\\x=-\dfrac{11}{6}\end{array} \right.\)
Vậy `x = \frac{-7}{6}` hoặc `x = \frac{-11}{6}`
