Giải thích các bước giải:
b) $\bigg(x+\dfrac{7}{4}\bigg)^2 = \dfrac{16}{25}=\bigg(\dfrac{4}{5}\bigg)^2 = \bigg(-\dfrac{4}{5}\bigg)^2$
$\to \left[ \begin{array}{l}x+\dfrac{7}{4} = \dfrac{4}{5}\\x+\dfrac{7}{4} = \dfrac{-4}{5}\end{array} \right. $
$\to \left[ \begin{array}{l}x=\dfrac{4}{5}-\dfrac{7}{4}\\x=\dfrac{-4}{5} - \dfrac{7}{4}\end{array} \right.$
$\to \left[ \begin{array}{l}x=-\dfrac{19}{20}\\x=\dfrac{-51}{20}\end{array} \right.$
