Вопрос:

Найдите значения выражений: 1) \(69\left(\frac{1}{23}\right)^2+\frac{20}{23}\); 2) \(\frac{0,14}{1-\frac{17}{24}}\); 3) \(\frac{0,83-1,07}{-1,5\cdot(-0,4)}\); 4) \((-3,2+1\frac{1}{3})\cdot4,5\); 5) \(-\sqrt{(-2,2)^2}:1\frac{4}{7}\).

Ответ:

  1. \[69\left(\frac{1}{23}\right)^2+\frac{20}{23}=69\cdot\frac{1}{529}+\frac{20}{23}=\frac{3}{23}+\frac{20}{23}=1.\]
  2. \[\frac{0.14}{1-\frac{17}{24}}=\frac{0.14}{\frac{7}{24}}=0.14\cdot\frac{24}{7}=0.48.\]
  3. \[\frac{0.83-1.07}{-1.5\cdot(-0.4)}=\frac{-0.24}{0.6}=-0.4.\]
  4. \[\left(-3.2+1\frac{1}{3}\right)\cdot4.5=\left(-\frac{16}{5}+\frac{4}{3}\right)\cdot\frac{9}{2}=\left(-\frac{28}{15}\right)\cdot\frac{9}{2}=-\frac{42}{5}=-8.4.\]
  5. \[-\sqrt{(-2.2)^2}:1\frac{4}{7}=-2.2:\frac{11}{7}=-2.2\cdot\frac{7}{11}=-1.4.\]

Ответ: 1) 1; 2) 0,48; 3) −0,4; 4) −8,4; 5) −1,4.