Tìm x , biết: g) x/3 = 2/3 + − 1/7
Giải thích
g) \[\frac{x}{3} = \frac{2}{3} + \frac{{ - 1}}{7}\]
\[\frac{x}{3} = \frac{{14}}{{21}} + \frac{{ - 3}}{{21}}\]
\[\frac{x}{3} = \frac{{11}}{{21}}\]
Suy ra \[x \cdot 21 = 3 \cdot 11\]
\(21x = 33\)
\[x = \frac{{33}}{{21}} = \frac{{11}}{7}.\]
Vậy \[x = \frac{{11}}{7}.\]