thực hiện phép tính ạ giúp em đang cần gấp ạ

Answer:

$\color{red}{a)}\; \dfrac2{15} - \dfrac7{10}$

$= \dfrac4{30} - \dfrac{21}{30}$

$= \dfrac{-17}{30}$

$\color{red}{b)}\; \dfrac{-3}{14} + \dfrac2{21}$

$= \dfrac{-18}{84} + \dfrac8{84}$

$= \dfrac{-10}{84} = \dfrac{-5}{42}$

$\color{red}{c)}\; \dfrac{-6}9 + \dfrac{-12}{16}$

$= \dfrac{-2}3 + \dfrac{-3}4$

$= \dfrac{-8}{12} + \dfrac{-9}{12}$

$= \dfrac{-17}{12}$