Question

 

Tính hợp lí nếu có thể

-5/7 + -3/-5 + 5/7

Answer 1

\(\frac{-5}{7}+\frac{-3}{-5}+\frac{5}{7}\)

\(=\left(\frac{-5}{7}+\frac{5}{7}\right)+\frac{-3}{-5}\)

\(=0+\frac{-3}{-5}\)

\(=\frac{-3}{-5}\)

Answer 2

-5/7 + -3/-5 + 5/7

= ( -5/7 + 5/7 ) + -3/-5 

=        0 + -3/-5

=        -3/-5

=     3/5 

Answer 3

= -5/7 + -3/-5 + 5/7 

= ( 5/7 + -5/7 ) + -3/-5

= 0/7 + -3/-5 

=0 + -3/-5

=-3/-5

Answer 4

= ( -5/7 + 5/7) + -3/-5

=0 + -3/-5

=-3/-5