Question

thực hiện phép tính (tính nhanh nếu có thể)

Answer 1

k.

$=\frac{-5}{7}(\frac{2}{11}+\frac{9}{11})+\frac{12}{7}$

$=\frac{-5}{7}.\frac{11}{11}+\frac{12}{7}$

$=\frac{-5}{7}+\frac{12}{7}=\frac{7}{7}=1$

l.

$=(\frac{1}{5}+\frac{4}{5})+(\frac{-2}{9}+\frac{-7}{9})+\frac{16}{17}$

$=\frac{5}{5}+\frac{-9}{9}+\frac{16}{17}$

$=1+(-1)+\frac{16}{17}=\frac{16}{17}$