Đáp án:
b)B=$\frac{-3}{5}$ .$\frac{2}{7}$ +$\frac{-3}{5}$ .$\frac{5}{7}$ +2$\frac{3}{5}$
=$\frac{-3}{5}$ .($\frac{2}{7}$ +$\frac{5}{7}$ )+2$\frac{3}{5}$
=$\frac{-3}{5}$ .1+2$\frac{3}{5}$
=2
d)$8^{2}$ -(235+67)+235-13
=64-67-13-235+235
=64-80-0
=-16
Xin hay nhất.