Đáp án:
B2:
c) \(x = \dfrac{1}{2}\)
Giải thích các bước giải:
\(\begin{array}{l}
B1:\\
b)2 + \dfrac{7}{{19}} + 3 + \dfrac{5}{{13}} - 2 - \dfrac{5}{{13}}\\
= 3 + \dfrac{7}{{19}} = \dfrac{{64}}{{19}}\\
c)\left( { - \dfrac{{23}}{5} + 1 + \dfrac{1}{9} + \dfrac{8}{5} + \dfrac{8}{9}} \right).2021\\
= \left( { - 3 + 1 + 1} \right).2021 = - 1.2021 = - 2021\\
B2:\\
c)\dfrac{3}{4}.x + \dfrac{1}{4}x - \dfrac{1}{6} = \dfrac{1}{3}\\
\to x = \dfrac{1}{3} + \dfrac{1}{6}\\
\to x = \dfrac{1}{2}
\end{array}\)
