Question

Вычислите: 1)3/8*(-4)+5; 2)5/9:(-1/3)-7; 3)2/5*(-3)-4/5; 4)5/12:1/4-(-1/3); 5)(1/2)*(-4)-5; 6)4/9:(-2/3)+1.

Answer 1

Давайте поочередно решим каждое уравнение:

1) \( \frac{3}{8} \cdot (-4) + 5 \):

\[ = -\frac{12}{8} + 5 \] \[ = -\frac{3}{2} + \frac{10}{2} \] \[ = \frac{-3 + 10}{2} \] \[ = \frac{7}{2} \]

Ответ: \( \frac{7}{2} \)

2) \( \frac{5}{9} : \left(-\frac{1}{3}\right) - 7 \):

\[ = \frac{5}{9} \cdot \left(-\frac{3}{1}\right) - 7 \] \[ = -\frac{15}{9} - 7 \] \[ = -\frac{5}{3} - \frac{21}{3} \] \[ = -\frac{26}{3} \]

Ответ: \( -\frac{26}{3} \)

3) \( \frac{2}{5} \cdot (-3) - \frac{4}{5} \):

\[ = -\frac{6}{5} - \frac{4}{5} \] \[ = -\frac{10}{5} \] \[ = -2 \]

Ответ: \( -2 \)

4) \( \frac{5}{12} : \frac{1}{4} - \left(-\frac{1}{3}\right) \):

\[ = \frac{5}{12} \cdot \frac{4}{1} - \left(-\frac{1}{3}\right) \] \[ = \frac{5}{3} + \frac{1}{3} \] \[ = \frac{6}{3} \] \[ = 2 \]

Ответ: \( 2 \)

5) \( \frac{1}{2} \cdot (-4) - 5 \):

\[ = -2 - 5 \] \[ = -7 \]

Ответ: \( -7 \)

6) \( \frac{4}{9} : \left(-\frac{2}{3}\right) + 1 \):

\[ = \frac{4}{9} \cdot \left(-\frac{3}{2}\right) + 1 \] \[ = -\frac{12}{18} + 1 \] \[ = -\frac{2}{3} + \frac{18}{18} \] \[ = -\frac{2}{3} + 1 \] \[ = \frac{-2 + 3}{3} \] \[ = \frac{1}{3} \]

Ответ: \( \frac{1}{3} \)