Respuesta :

you have to first make like terms 

[tex] -\frac{2}{7} -(- \frac{4}{3})- \frac{1}{3} [/tex]
**you want the denominator to be 21 

[tex] \frac{-6+28-7}{21} = \frac{15}{21}= \frac{5}{7} [/tex]