\[\boxed{\mathbf{Проверьте\ себя.\ Страница\ 81}}\]
\[\boxed{\mathbf{Проверочная\ работа.\ \ Раскрытие\ скобок}}\]
\[\boxed{\text{1.}}\]
\[\textbf{а)} - (18 - 6) = - 18 + 6 = - 12\]
\[\textbf{б)} - 6 + ( - 2 + 7) =\]
\[= - 6 - 2 + 7 = - 8 + 7 = - 1\]
\[\textbf{в)} - ( - 9,1 - 1,1) = 9,1 + 1,1 =\]
\[= 10,2\]
\[\textbf{г)} - \left( 3\frac{11}{18} - 5,7 \right) + \left( 4\frac{17}{18} + 2,3 \right) =\]
\[= - 3\frac{11}{18} + 5,7 + 4\frac{17}{18} + 2,3 =\]
\[= 8 + 1\frac{6}{18} =\]
\[= 8 + 1\frac{1}{3} = 9\frac{1}{3}\]
\[\boxed{\text{2.}}\]
\[\textbf{а)}\ 9 + (12 - 8) = 9 + 12 - 8\]
\[\textbf{б)} - 2,5 - ( - 0,3) + 7 =\]
\[= - 2,5 + 0,3 + 7\]
\[\boxed{\text{3.}}\]
\[\textbf{а)}\ (x + 12) + (16 - x) =\]
\[= x + 12 + 16 - x = 28\]
\[\textbf{б)}\ (a - b) + (b - a + c) =\]
\[= a - b + b - a + c = c\ \]
\[\boxed{\text{4.}}\]
\[- 8 + (u - 42) = - 7\]
\[- 8 + y - 42 = - 7\]
\[- 50 + u = - 7\]
\[u = - 7 - ( - 50)\]
\[u = - 7 + 50\]
\[u = 43.\]
Глава 38. Коэффициент