Đáp án:
$\text{a) x = $\dfrac{7}{2}$.}$
$\text{b) x = $\dfrac{-51}{10}$.}$
$\text{c) x = $\dfrac{-1}{3}$.}$
Giải thích các bước giải:
$\text{a) x + $\dfrac{1}{2}$ = $2^5$ ÷ $2^3$.}$
$\text{⇒ x + $\dfrac{1}{2}$ = $2^2$.}$
$\text{⇒ x + $\dfrac{1}{2}$ = 4.}$
$\text{⇒ x = 4 - $\dfrac{1}{2}$.}$
$\text{⇒ x = $\dfrac{8}{2}$ - $\dfrac{1}{2}$.}$
$\text{⇒ x = $\dfrac{7}{2}$.}$
$\text{Vậy x = $\dfrac{7}{2}$.}$
$\text{b) 6 - ($\dfrac{1}{2}$ - x) = $\dfrac{2}{5}$.}$
$\text{⇒ $\dfrac{1}{2}$ - x = 6 - $\dfrac{2}{5}$.}$
$\text{⇒ $\dfrac{1}{2}$ - x = $\dfrac{30}{5}$ - $\dfrac{2}{5}$.}$
$\text{⇒ $\dfrac{1}{2}$ - x = $\dfrac{28}{5}$.}$
$\text{⇒ x = $\dfrac{1}{2}$ - $\dfrac{28}{5}$.}$
$\text{⇒ x = $\dfrac{5}{10}$ - $\dfrac{56}{10}$.}$
$\text{⇒ x = $\dfrac{-51}{10}$.}$
$\text{Vậy x = $\dfrac{-51}{10}$.}$
$\text{c) $(\dfrac{-1}{3})^3$.x = $\dfrac{1}{81}$.}$
$\text{⇒ $\dfrac{-1}{27}$.x = $\dfrac{1}{81}$.}$
$\text{⇒ x = $\dfrac{1}{81}$ ÷ $\dfrac{-1}{27}$.}$
$\text{⇒ x = $\dfrac{1}{81}$.$\dfrac{-27}{1}$.}$
$\text{⇒ x = $\dfrac{-1}{3}$.}$
$\text{Vậy x = $\dfrac{-1}{3}$.}$
