`B=[-7]/3 . 15/9-10/9=[-7.3.5]/[3.9]-10/9=[-35]/9-10/9=[-45]/9=-5`
\(\dfrac{-7}{3}\cdot\dfrac{15}{9}-\dfrac{10}{9}=-\dfrac{35}{9}-\dfrac{10}{9}=-\dfrac{45}{9}=-5\)
b. B = \(\dfrac{-35}{9}\)- \(\dfrac{10}{9}\)= \(\dfrac{-45}{9}\)= -5
`#Q`
\(=\dfrac{-7}{9}.5-\dfrac{10}{9}=-\dfrac{35}{9}-\dfrac{10}{9}\)
\(=-\dfrac{35}{9}-\dfrac{10}{9}=-\dfrac{45}{9}=-5\)
Vậy `B=-5`

4 và 5