Задание 183

Решение:

• $${\largeа)}\ 2:\left({-}6\frac{7}{13}+3\frac{17}{39}\right)=2:\left({-}6\frac{21}{39}+3\frac{17}{39}\right)=2:\left({-}3\frac{4}{39}\right)=2:\left({-}\frac{121}{39}\right)=2\cdot\left({-}\frac{39}{121}\right)={-}\frac{78}{121}$$

• $${\largeб)}\ \left(3{,}5\cdot24-5\frac{2}{3}:\frac{1}{18}\right)\cdot5=\left(3\frac{1}{2}\cdot24-5\frac{2}{3}:\frac{1}{18}\right)\cdot5=\left(\frac{7}{2}\cdot24-\frac{17}{3}\cdot18\right)\cdot5=(7\cdot12-17\cdot6)\cdot5=(84-102)\cdot5={-}18\cdot5={-}90$$

• $${\largeв)}\ 3\cdot\left(5\frac{4}{9}-6\frac{5}{18}\right)=3\cdot\left(5\frac{8}{18}-6\frac{5}{18}\right)=3\cdot\left(5\frac{8}{18}-5\frac{23}{18}\right)=3\cdot\left({-}\frac{15}{18}\right)=3\cdot\left({-}\frac{5}{6}\right)={-}\frac{5}{2}={-}2\frac{1}{2}={-}2{,}5$$

• $${\largeг)}\ \left({-}12\frac{2}{3}\right):3\frac{1}{6}+13{,}5:4{,}5=\left({-}\frac{38}{3}\right):\frac{19}{6}+135:45=\left({-}\frac{38}{3}\right)\cdot\frac{6}{19}+3={-}2\cdot2+3={-}4+3={-1}$$

• $${\largeд)}\ 6\cdot({-}1{,}25)+({-}4):\left({-}1\frac{1}{3}\right)={-}7{,}5+({-}4):\left({-}\frac{4}{3}\right)={-}7{,}5+({-}4)\cdot\left({-}\frac{3}{4}\right)={-}7{,}5+3={-}4{,}5$$

• $${\largeе)}\ \left(4{,}3-5\frac{4}{15}\right)\cdot4\frac{4}{29}-2{,}5\cdot2=\left(4\frac{3}{10}-5\frac{4}{15}\right)\cdot\frac{120}{29}-5=\left(4\frac{9}{30}-5\frac{8}{30}\right)\cdot\frac{120}{29}-5=\left(4\frac{9}{30}-4\frac{38}{30}\right)\cdot\frac{120}{29}-5={-}\frac{29}{30}\cdot\frac{120}{29}-5={-}4-5={-}9$$