6. Вычислите значение выражения наиболее удобным спосо- бом: 3 3 a) - ⋅ 11 - - = - 8 8 ⋅ 11 + (- ⋅ 3 - )⋅ 1 = - ⋅( 8 8 + )= б) 0,8 ⋅ (-2,1) + 1,2 ⋅ (-2,1) = = в) (5 + 13)⋅(-12) = - ⋅(-12) + = г) -15 ⋅ (4 - 7) 10 5 = -15 ⋅ (4 + (-1)) = 5

Ответ: a) -\frac{33}{8}, б) -3.36, в) -22, г) 4.5

а) \(-\frac{3}{8} \cdot 11 - \frac{3}{8} = -\frac{3}{8} \cdot 11 + \left(-\frac{3}{8}\right) \cdot 1 = -\frac{3}{8} \cdot (11 + 1) = -\frac{3}{8} \cdot 12 = -\frac{36}{8} = -\frac{9}{2} = -4\frac{1}{2} = -4.5\)

б) \(0,8 \cdot (-2,1) + 1,2 \cdot (-2,1) = (-2,1) \cdot (0,8 + 1,2) = (-2,1) \cdot 2 = -4,2\)

в) \(\left(\frac{5}{6} + 1\frac{2}{3}\right) \cdot (-12) = \frac{5}{6} \cdot (-12) + 1\frac{2}{3} \cdot (-12) = \frac{5}{6} \cdot (-12) + \frac{5}{3} \cdot (-12) = -10 - 20 = -30\)

г) \(-15 \cdot \left(\frac{4}{5} - \frac{7}{10}\right) = -15 \cdot \left(\frac{4}{5} + \left(-\frac{7}{10}\right)\right) = -15 \cdot \left(\frac{8}{10} - \frac{7}{10}\right) = -15 \cdot \frac{1}{10} = -1.5\)

Ответ: a) -\frac{33}{8}, б) -3.36, в) -22, г) 4.5