($\frac{5}{11}$ + $\frac{6}{12}$) . 3 - ($\frac{18}{11}$ + $\frac{22}{12}$) . 3
= ($\frac{5}{11}$ . 3 + $\frac{6}{12}$ . 3) - ($\frac{18}{11}$ . 3 + $\frac{22}{12}$ . 3)
= ($\frac{15}{11}$ + $\frac{18}{12}$) - ($\frac{54}{11}$ + $\frac{66}{12}$)
= ($\frac{15}{11}$ - $\frac{54}{11}$) + ($\frac{18}{12}$ - $\frac{66}{12}$)
= $\frac{-39}{11}$ + $\frac{-48}{12}$
= $\frac{-39}{11}$ + (-4)
= $\frac{-83}{11}$
= -7$\frac{6}{11}$
Chúc học tốt!!!
