A. \[1\frac{1}{7}\]
B. \[\frac{2}{7}\]
C. \[\frac{6}{7}\]
D. \[\frac{7}{8}\]
Giải bởi Vietjack
\[\begin{array}{*{20}{l}}{x - 3\frac{1}{2}x = - \frac{{20}}{7}}\\{x - \frac{7}{2}x = - \frac{{20}}{7}}\\{x.\left( {1 - \frac{7}{2}} \right) = - \frac{{20}}{7}}\\{x.\left( {\frac{{ - 5}}{2}} \right) = \frac{{ - 20}}{7}}\\{x = \frac{{ - 20}}{7}:\frac{{ - 5}}{2}}\\{x = \frac{{ - 20}}{7}.\frac{2}{{ - 5}}}\\{x = \frac{8}{7}}\\{x = 1\frac{1}{7}}\end{array}\]
Đáp án cần chọn là: A
a) 125dm2b) 218cm2c) 240dm2d) 34cm2
\[3\frac{3}{4}\] tạ; \[\frac{{377}}{{100}}\] tạ; \[\frac{7}{2}\] tạ; \[3\frac{{45}}{{100}}\] tạ; 365 kg.
