Bài ${1}$:

${a)}$ $\frac{-5}{11}$.$\frac{7}{15}$.$\frac{11}{-5}$.${-30}$ 

= $\frac{-5.7.11.-30}{11.15.-5}$

= ${-14}$

${b)}$ ($\frac{11}{23}$ : $\frac{33}{16}$). $\frac{3}{5}$ 
= ($\frac{11}{23}$ . $\frac{16}{33}$).$\frac{3}{5}$ 
= $\frac{1}{6}$.$\frac{3}{5}$ 
=  $\frac{1}{10}$ 

${c)}$ $\frac{-5}{9}$. $\frac{3}{11}$ +$\frac{-13}{18}$ .  $\frac{3}{11}$
=  $\frac{3}{11}$ .( $\frac{-5}{9}$ + $\frac{-13}{18}$)
=  $\frac{3}{11}$ . $\frac{-23}{18}$ 
=  $\frac{-23}{66}$

Bài ${2}$

${a)} : C

${b)} : C

${CHÚC HỌC TỐT!!}$

Bài $2$:

a) Đáp án $B.$

b) Đáp án $C.$

Bài $1$:

$a)\dfrac{-5}{11}.\dfrac{7}{15}.\dfrac{11}{-5}.(-30)$

$=(\dfrac{-5}{11}.\dfrac{11}{-5}).[\dfrac{7}{15}.(-30)]$

$=1.\dfrac{7.(-30)}{15}$

$=\dfrac{7.(-2)}{1}$

$=-14$

Vậy giá trị biểu thức là $-14.$

$b)(\dfrac{11}{12}÷\dfrac{33}{16}).\dfrac{3}{5}$

$=\dfrac{11}{12}.\dfrac{16}{33}.\dfrac{3}{5}$

$=\dfrac{11.16.3}{12.33.5}$

$=\dfrac{11.48}{12.33.5}$

$=\dfrac{1.4}{1.3.5}$

$=\dfrac{4}{15}$

Vậy giá trị biểu thức là $\dfrac{4}{15}$$.$

$c)\dfrac{-5}{9}.\dfrac{3}{11}+\dfrac{-13}{18}.\dfrac{3}{11}$

$=\dfrac{-10}{18}.\dfrac{3}{11}+\dfrac{-13}{18}.\dfrac{3}{11}$

$=(\dfrac{-10}{18}+\dfrac{-13}{18}).\dfrac{3}{11}$

$=\dfrac{-23}{18}.\dfrac{3}{11}$

$=\dfrac{(-23).3}{18.11}$

$=\dfrac{(-23).1}{6.11}$

$=\dfrac{-23}{66}$

Vậy giá trị biểu thức là $\dfrac{-23}{66}$$.$

CHÚC BẠN HOK TỐT!!!!