Bạn tham khảo!
$3$ $.$ $($ $5x$ $+$ $\dfrac{2}{3}$ $)^{2}$ $=$ $\dfrac{4}{3}$
$⇒$ $($ $5x$ $+$ $\dfrac{2}{3}$ $)^{2}$ $=$ $\dfrac{4}{9}$
$⇒$ $($ $5x$ $+$ $\dfrac{2}{3}$ $)^{2}$ $=$ $($ $\dfrac{2}{3}$ $)^{2}$ hoặc $($ $5x$ $+$ $\dfrac{2}{3}$ $)^{2}$ $=$ $($ $\dfrac{-2}{3}$ $)^{2}$
$⇒$ $5x$ $+$ $\dfrac{2}{3}$ $=$ $\dfrac{2}{3}$ hoặc $5x$ $+$ $\dfrac{2}{3}$ $=$ $\dfrac{-2}{3}$
$⇒$ $5x$ $=$ $0$ hoặc $5x$ $=$ $\dfrac{-4}{3}$
$⇒$ $x$ $=$ $0$ hoặc $x$ $=$ $\dfrac{-4}{15}$
Vậy $x$ $=$ $0$ hoặc $x$ $=$ $\dfrac{-4}{15}$
$FbBinhne2k88$
