Question

tính hợp lí

(1/2-13/14):5/7-(-2/21+1/7):5/7

 

 

Answer 1

=(7/14- 13/14):5/7-(-2/21+3/21):5/7

=-6/14* 7/5 -1/21*7/5

=(-6/14-1/21)*7/5

=-10/21*7/5

=-2/3

MÌNH CHẮC CHẮN VỚI BẠN LUÔN!!!!

Answer 2

\(\left(\frac{1}{2}-\frac{13}{14}\right):\frac{5}{7}-\left(-\frac{2}{21}+\frac{1}{7}:\frac{5}{7}\right)\)
\(=\left(\frac{7}{14}-\frac{13}{14}\right):\frac{5}{7}-\left(-\frac{2}{21}+\frac{3}{21}\right):\frac{5}{7}\)
\(=-\frac{6}{14}\times\frac{7}{5}-\frac{1}{21}\times\frac{7}{5}\)
\(=\left(-\frac{6}{14}-\frac{1}{21}\right)\times\frac{7}{5}\)
\(=-\frac{10}{21}\times\frac{7}{5}\)
\(=-\frac{2}{3}\)
\("k\)\(nha"\)