Tính giá trị biểu thức: (8-9/4+2/7)-(-6-3/7+5/4)-(3+2/4-9/7)

Trả lời

$\left(8-\frac{9}{4}+\frac{2}{7}\right)-\left(-6-\frac{3}{7}+\frac{5}{4}\right)-\left(3+\frac{2}{4}-\frac{9}{7}\right)$

= $8-\frac{9}{4}+\frac{2}{7}+6+\frac{3}{7}-\frac{5}{4}-3-\frac{2}{4}+\frac{9}{7}$

= $8-\frac{9}{4}+\frac{2}{7}+6+\frac{3}{7}-\frac{5}{4}-3-\frac{2}{4}+\frac{9}{7}$

= (8 + 6 – 3) + $\left(\frac{-9}{4}-\frac{5}{4}-\frac{2}{4}\right)+\left(\frac{2}{7}+\frac{3}{7}+\frac{9}{7}\right)$

= 11+ $\left(-\frac{16}{4}\right)+\frac{14}{7}$

= 11+(-4)+2 = 9