\[\boxed{\mathbf{Страница\ 39.\ }\mathbf{Еуроки\ - \ ДЗ\ без\ мороки}}\]
\[\boxed{\mathbf{3.\ }}\]
\[96 + (49 - x) = 105\]
\[Если\ x = 28 \Longrightarrow \ \ \]
\[96 + (49 - x) =\]
\[= 96 + (49 - 28) =\]
\[= 96 + 21 = 117\]
\[Если\ x = 0 \Longrightarrow\]
\[96 + (49 - x) =\]
\[= 96 + (49 - 0) =\]
\[= 96 + 49 = 145\]
\[Если\ x = 12 \Longrightarrow\]
\[96 + (49 - x) =\]
\[= 96 + (49 - 12) =\]
\[= 96 + 37 = 133\]
\[Если\ x = 40 \Longrightarrow\]
\[96 + (49 - x) =\]
\[= 96 + (49 - 40) =\]
\[= 96 + 9 = 105\]
\[Вывод:корнем\ уравнения\ \]
\[будет\ число\ 40.\]
\[\boxed{\mathbf{4.\ }}\]
\[x \cdot (6 - x) = 0\]
\[x = 0;\ \ \ x = 6.\]
\[Ответ:0;\ \ 6.\]
\[\boxed{\mathbf{5.\ }}\]
\[\mathbf{а)\ правильно;}\]
\[\textbf{б)}\ неправильно:\]
\[a + 84 = 158\]
\[a = 158 - 84\]
\[a = 74.\]
\[\textbf{в)}\ неправильно:\]
\[196 + b = 400\]
\[b = 400 - 196\]
\[b = 204.\]
\[\textbf{г)}\ неправильно:\]
\[x - 316 = 16\]
\[x = 16 + 316\]
\[x = 332.\]
\[\textbf{д)}\ правильно;\]
\[\textbf{е)}\ неправильно:\]
\[452 - x = 35\]
\[x = 452 - 35\]
\[x = 417.\]
\[\textbf{ж)}\ правильно.\]