2/3 + x = 45% ( tìm x )

$\text{$\dfrac{2}{3}$ + x = 45%}$

$\text{⇒ $\dfrac{2}{3}$ + x = $\dfrac{9}{20}$}$

$\text{⇒ x = $\dfrac{9}{20}$ - $\dfrac{2}{3}$}$

$\text{⇒ x = -$\dfrac{13}{60}$}$

$\text{Vậy x = -$\dfrac{13}{60}$}$