Bạn tham khảo :
d )
$\dfrac{1}{3} + \dfrac{2}{3}(x-\dfrac{1}{2} = (\dfrac{1}{7})^{10} . 7^{10} - 1 \dfrac{1}{4}$
$\dfrac{1}{3} + \dfrac{2}{3}(x-\dfrac{1}{2}) = 1 - \dfrac{5}{4}$
$\dfrac{1}{3} + \dfrac{2}{3}(x-\dfrac{1}{2} )= \dfrac{-1}{4}$
⇒ $ \dfrac{2}{3}(x-\dfrac{1}{2} )= \dfrac{-7}{12}$
⇒ $x - \dfrac{1}{2} = \dfrac{-7}{18}$
⇒ $x =\dfrac{1}{9}$