1. Thực hiện phép tính (tính nhanh nếu có thể): a)1/8- 9/8.4/3; 2. Tìm x: a) x/- 16 =- 1/6.3/4;
1.
a) \(\frac{1}{8} - \frac{9}{8}.\frac{4}{3}\)\( = \frac{1}{8} - \frac{3}{2}\)\( = \frac{1}{8} - \frac{{12}}{8}\)\( = \frac{{ - 11}}{8}\);
b) \[\frac{{ - 3}}{4}.\frac{{2022}}{{2023}} - \frac{{2022}}{{2023}}.\frac{1}{4}\]\[ = \frac{{2022}}{{2023}}.\left( {\frac{{ - 3}}{4} - \frac{1}{4}} \right)\]
\[ = \frac{{2022}}{{2023}}.\left( { - 1} \right)\]\[ = - \frac{{2022}}{{2023}}\].
2.
a) \[\frac{x}{{ - 16}} = \frac{{ - 1}}{6}.\frac{3}{4}\] \[\frac{x}{{ - 16}} = \frac{{ - 3}}{{24}}\] \[x = \frac{{ - 3}}{{24}}.\left( { - 16} \right)\] \[x = 2\] Vậy \[x = 2\]. | b) \[\frac{1}{2}x + \frac{1}{8}x = \frac{3}{4}\] \[\left( {\frac{1}{2} + \frac{1}{8}} \right)x = \frac{3}{4}\] \[\frac{5}{8}x = \frac{3}{4}\] \[x = \frac{3}{4}:\frac{5}{8}\] \[x = \frac{6}{5}\] Vậy \[x = \frac{6}{5}\]. |