Làm hộ tôi nhanh vs 4h phải nộp r

Đáp án:

Giải thích các bước giải:

a)

$\dfrac{5}{22} + \dfrac{-7}{6} + \dfrac{-5}{22}$

$= \left( \dfrac{5}{22} + \dfrac{-5}{22} \right) + \dfrac{-7}{6}$

$= 0 + \dfrac{-7}{6} = -\dfrac{7}{6}$

b)

$\dfrac{-5}{9} + \dfrac{3}{4} - \dfrac{4}{9} + \dfrac{1}{4}$

$= \left( \dfrac{-5}{9} - \dfrac{4}{9} \right) + \left( \dfrac{3}{4} + \dfrac{1}{4} \right)$

$= \dfrac{-9}{9} + \dfrac{4}{4} = -1 + 1 = 0$

c)

$\left( \dfrac{1}{4} - \dfrac{7}{6} \right) - \left( \dfrac{-7}{6} - \dfrac{7}{4} \right)$

$= \dfrac{1}{4} - \dfrac{7}{6} + \dfrac{7}{6} + \dfrac{7}{4}$

$= \left( \dfrac{1}{4} + \dfrac{7}{4} \right) + \left( -\dfrac{7}{6} + \dfrac{7}{6} \right)$

$= \dfrac{8}{4} + 0 = 2$

d)

$\dfrac{-7}{8} \cdot \dfrac{7}{11} + \dfrac{-7}{8} \cdot \dfrac{4}{11}$

$= \dfrac{-7}{8} \cdot \left( \dfrac{7}{11} + \dfrac{4}{11} \right)$

$= \dfrac{-7}{8} \cdot \dfrac{11}{11}$

$= \dfrac{-7}{8} \cdot 1 = -\dfrac{7}{8}$