Страницы 8-9 номер 1.1.30, ГДЗ по алгебре за 7, 8 и 9 класс к задачнику Ткачевой
Найти значение выражения: 1) \(5\frac{1}{2} - 7{,}21 - 3{,}2 : (-8)\); 2) \(-4\frac{3}{14} + 6\frac{1}{21} - 0{,}48 : (-0{,}6)\); 3) \(\frac{2}{7} : (1{,}5 + (-2{,}1 + 4{,}5 \cdot 3))\); 4) \(\left(3\frac{2}{5} - 1{,}6\right) \cdot (-7{,}1 - (-0{,}5 + 1{,}2 \cdot 4))\); 5) \(\frac{5{,}6 - 24 \cdot 2{,}4 - 12}{-15{,}6 : 5{,}2 + 2{,}2}\); 6) \(\frac{-2{,}5 + 3{,}5 \cdot 0{,}4 + 5}{4{,}41 - 2{,}7 : 3\frac{1}{3}}\); 7) \(-12 + 2\frac{1}{3} : \left(0{,}5 - \left(3{,}2 + 4\frac{3}{8} \cdot \frac{1}{2}\right)\right)\); 8) \(0{,}65 - 3\frac{1}{2} \cdot \left(-2{,}4 + \left(1{,}7 - 0{,}3 : \frac{3}{5}\right)\right)\).
1) \(5\frac{1}{2} - 7{,}21 - 3{,}2 : (-8) = 5{,}5 - 7{,}21 + 0{,}4 = -1{,}71 + 0{,}4 = -1{,}31\);
2) \(-4\frac{3}{14} + 6\frac{1}{21} - 0{,}48 : (-0{,}6) = -4\frac{9}{42} + 6\frac{2}{42} + 0{,}8 = 1\frac{5}{6} + \frac{4}{5} = 1\frac{49}{30} = 2\frac{19}{30}\);
3) \(\frac{2}{7} : (1{,}5 + (-2{,}1 + 4{,}5 \cdot 3)) = \frac{2}{7} : (1{,}5 + 11{,}4) = \frac{2}{7} : 12{,}9 = \frac{2}{7} \cdot \frac{10}{129} = \frac{20}{903}\);
4) \(\left(3\frac{2}{5} - 1{,}6\right) \cdot (-7{,}1 - (-0{,}5 + 1{,}2 \cdot 4)) = (3{,}4 - 1{,}6) \cdot (-7{,}1 - 4{,}3) = 1{,}8 \cdot (-11{,}4) = -20{,}52\);
5) \(\frac{5{,}6 - 24 \cdot 2{,}4 - 12}{-15{,}6 : 5{,}2 + 2{,}2} = \frac{5{,}6 - 57{,}6 - 12}{-3 + 2{,}2} = \frac{-64}{-0{,}8} = 80\);
6) \(\frac{-2{,}5 + 3{,}5 \cdot 0{,}4 + 5}{4{,}41 - 2{,}7 : 3\frac{1}{3}} = \frac{-2{,}5 + 1{,}4 + 5}{4{,}41 - 2{,}7 \cdot \frac{3}{10}} = \frac{3{,}9}{3{,}6} = \frac{13}{12} = 1\frac{1}{12}\);
7)
\[\begin{aligned} &-12 + 2\frac{1}{3} : \left(0{,}5 - \left(3{,}2 + 4\frac{3}{8} \cdot \frac{1}{2}\right)\right) = -12 + 2\frac{1}{3} : \left(0{,}5 - 5\frac{31}{80}\right) = {} \\ &= -12 + \frac{7}{3} : \left(-\frac{391}{80}\right) = -12 - \frac{7 \cdot 80}{3 \cdot 391} = -12\frac{560}{1173}. \end{aligned}\]
8) \(0{,}65 - 3\frac{1}{2} \cdot \left(-2{,}4 + \left(1{,}7 - 0{,}3 : \frac{3}{5}\right)\right) = 0{,}65 - 3{,}5 \cdot (-2{,}4 + (1{,}7 - 0{,}5)) = 0{,}65 - 3{,}5 \cdot (-1{,}2) = 0{,}65 + 4{,}2 = 4{,}85\).
Ответ: 1) \(-1{,}31\); 2) \(2\frac{19}{30}\); 3) \(\frac{20}{903}\); 4) \(-20{,}52\); 5) 80; 6) \(1\frac{1}{12}\); 7) \(-12\frac{560}{1173}\); 8) \(4{,}85\).
Найти значение выражения: 1) \(5\frac{1}{2} - 7{,}21 - 3{,}2 : (-8)\); 2) \(-4\frac{3}{14} + 6\frac{1}{21} - 0{,}48 : (-0{,}6)\); 3) \(\frac{2}{7} : (1{,}5 + (-2{,}1 + 4{,}5 \cdot 3))\); 4) \(\left(3\frac{2}{5} - 1{,}6\right) \cdot (-7{,}1 - (-0{,}5 + 1{,}2 \cdot 4))\); 5) \(\frac{5{,}6 - 24 \cdot 2{,}4 - 12}{-15{,}6 : 5{,}2 + 2{,}2}\); 6) \(\frac{-2{,}5 + 3{,}5 \cdot 0{,}4 + 5}{4{,}41 - 2{,}7 : 3\frac{1}{3}}\); 7) \(-12 + 2\frac{1}{3} : \left(0{,}5 - \left(3{,}2 + 4\frac{3}{8} \cdot \frac{1}{2}\right)\right)\); 8) \(0{,}65 - 3\frac{1}{2} \cdot \left(-2{,}4 + \left(1{,}7 - 0{,}3 : \frac{3}{5}\right)\right)\).
1) \(5\frac{1}{2} - 7{,}21 - 3{,}2 : (-8) = 5{,}5 - 7{,}21 + 0{,}4 = -1{,}71 + 0{,}4 = -1{,}31\);
2) \(-4\frac{3}{14} + 6\frac{1}{21} - 0{,}48 : (-0{,}6) = -4\frac{9}{42} + 6\frac{2}{42} + 0{,}8 = 1\frac{5}{6} + \frac{4}{5} = 1\frac{49}{30} = 2\frac{19}{30}\);
3) \(\frac{2}{7} : (1{,}5 + (-2{,}1 + 4{,}5 \cdot 3)) = \frac{2}{7} : (1{,}5 + 11{,}4) = \frac{2}{7} : 12{,}9 = \frac{2}{7} \cdot \frac{10}{129} = \frac{20}{903}\) — деление на \(12{,}9 = \frac{129}{10}\) заменено умножением на обратную дробь;
4) \(\left(3\frac{2}{5} - 1{,}6\right) \cdot (-7{,}1 - (-0{,}5 + 1{,}2 \cdot 4)) = (3{,}4 - 1{,}6) \cdot (-7{,}1 - 4{,}3) = 1{,}8 \cdot (-11{,}4) = -20{,}52\);
5) \(\frac{5{,}6 - 24 \cdot 2{,}4 - 12}{-15{,}6 : 5{,}2 + 2{,}2} = \frac{5{,}6 - 57{,}6 - 12}{-3 + 2{,}2} = \frac{-64}{-0{,}8} = 80\);
6) \(\frac{-2{,}5 + 3{,}5 \cdot 0{,}4 + 5}{4{,}41 - 2{,}7 : 3\frac{1}{3}} = \frac{-2{,}5 + 1{,}4 + 5}{4{,}41 - 2{,}7 \cdot \frac{3}{10}} = \frac{3{,}9}{3{,}6} = \frac{13}{12} = 1\frac{1}{12}\);
7)
\[\begin{aligned} &-12 + 2\frac{1}{3} : \left(0{,}5 - \left(3{,}2 + 4\frac{3}{8} \cdot \frac{1}{2}\right)\right) = -12 + 2\frac{1}{3} : \left(0{,}5 - 5\frac{31}{80}\right) = {} \\ &= -12 + \frac{7}{3} : \left(-\frac{391}{80}\right) = -12 - \frac{7 \cdot 80}{3 \cdot 391} = -12\frac{560}{1173}. \end{aligned}\]
8) \(0{,}65 - 3\frac{1}{2} \cdot \left(-2{,}4 + \left(1{,}7 - 0{,}3 : \frac{3}{5}\right)\right) = 0{,}65 - 3{,}5 \cdot (-2{,}4 + (1{,}7 - 0{,}5)) = 0{,}65 - 3{,}5 \cdot (-1{,}2) = 0{,}65 + 4{,}2 = 4{,}85\).
Ответ: 1) \(-1{,}31\); 2) \(2\frac{19}{30}\); 3) \(\frac{20}{903}\); 4) \(-20{,}52\); 5) 80; 6) \(1\frac{1}{12}\); 7) \(-12\frac{560}{1173}\); 8) \(4{,}85\).
