ГДЗ по алгебре 7 класс Абылкасымова параграф 22 - 22-3%i

1) Функция $y = 7,2 - 2,4x$. Выразим переменную $x$: $$2,4x = 7,2 - y$$ $$x = \frac{7,2 - y}{2,4}$$ * При $y = 1$: $$2,4x = 7,2 - 1$$ $$2,4x = 6,2$$ $$x = \frac{6,2}{2,4} = \frac{62}{24} = \frac{31}{12} = 2\frac{7}{12}$$ * При $y = -1$: $$2,4x = 7,2 - (-1)$$ $$2,4x = 7,2 + 1 = 8,2$$ $$x = \frac{8,2}{2,4} = \frac{82}{24} = \frac{41}{12} = 3\frac{5}{12}$$ * При $y = -\frac{2}{3}$: $$2,4x = 7,2 - \left(-\frac{2}{3}\right)$$ $$2,4x = \frac{36}{5} + \frac{2}{3} = \frac{108 + 10}{15} = \frac{118}{15}$$ $$x = \frac{118}{15} : 2,4 = \frac{118}{15} : \frac{12}{5} = \frac{118}{15} \cdot \frac{5}{12} = \frac{59 \cdot 1}{3 \cdot 6} = \frac{59}{18} = 3\frac{5}{18}$$ * При $y = 5$: $$2,4x = 7,2 - 5$$ $$2,4x = 2,2$$ $$x = \frac{2,2}{2,4} = \frac{22}{24} = \frac{11}{12}$$ 2) Функция $y = \frac{2}{3} + 6x$. Выразим переменную $x$: $$6x = y - \frac{2}{3}$$ $$x = \frac{y - \frac{2}{3}}{6}$$ * При $y = 1$: $$6x = 1 - \frac{2}{3}$$ $$6x = \frac{1}{3}$$ $$x = \frac{1}{3} : 6 = \frac{1}{18}$$ * При $y = -1$: $$6x = -1 - \frac{2}{3}$$ $$6x = -\frac{5}{3}$$ $$x = -\frac{5}{3} : 6 = -\frac{5}{18}$$ * При $y = -\frac{2}{3}$: $$6x = -\frac{2}{3} - \frac{2}{3}$$ $$6x = -\frac{4}{3}$$ $$x = -\frac{4}{3} : 6 = -\frac{4}{18} = -\frac{2}{9}$$ * При $y = 5$: $$6x = 5 - \frac{2}{3}$$ $$6x = \frac{13}{3}$$ $$x = \frac{13}{3} : 6 = \frac{13}{18}$$ 3) Функция $y = -\frac{3}{8}x + 7,5$. Выразим переменную $x$: $$\frac{3}{8}x = 7,5 - y$$ $$x = (7,5 - y) : \frac{3}{8} = (7,5 - y) \cdot \frac{8}{3}$$ * При $y = 1$: $$\frac{3}{8}x = 7,5 - 1 = 6,5$$ $$x = \frac{13}{2} \cdot \frac{8}{3} = \frac{13 \cdot 4}{1 \cdot 3} = \frac{52}{3} = 17\frac{1}{3}$$ * При $y = -1$: $$\frac{3}{8}x = 7,5 - (-1) = 7,5 + 1 = 8,5$$ $$x = \frac{17}{2} \cdot \frac{8}{3} = \frac{17 \cdot 4}{1 \cdot 3} = \frac{68}{3} = 22\frac{2}{3}$$ * При $y = -\frac{2}{3}$: $$\frac{3}{8}x = 7,5 - \left(-\frac{2}{3}\right) = \frac{15}{2} + \frac{2}{3} = \frac{45 + 4}{6} = \frac{49}{6}$$ $$x = \frac{49}{6} : \frac{3}{8} = \frac{49}{6} \cdot \frac{8}{3} = \frac{49 \cdot 4}{3 \cdot 3} = \frac{196}{9} = 21\frac{7}{9}$$ * При $y = 5$: $$\frac{3}{8}x = 7,5 - 5 = 2,5$$ $$x = \frac{5}{2} \cdot \frac{8}{3} = \frac{5 \cdot 4}{1 \cdot 3} = \frac{20}{3} = 6\frac{2}{3}$$ 4) Функция $y = -4,6x - 1\frac{1}{3}$. Выразим переменную $x$: $$4,6x = -1\frac{1}{3} - y$$ $$\frac{23}{5}x = -\left(y + \frac{4}{3}\right)$$ $$x = -\left(y + \frac{4}{3}\right) \cdot \frac{5}{23}$$ * При $y = 1$: $$\frac{23}{5}x = -1\frac{1}{3} - 1 = -\frac{7}{3}$$ $$x = -\frac{7}{3} \cdot \frac{5}{23} = -\frac{35}{69}$$ * При $y = -1$: $$\frac{23}{5}x = -\frac{4}{3} - (-1) = -\frac{4}{3} + 1 = -\frac{1}{3}$$ $$x = -\frac{1}{3} \cdot \frac{5}{23} = -\frac{5}{69}$$ * При $y = -\frac{2}{3}$: $$\frac{23}{5}x = -\frac{4}{3} - \left(-\frac{2}{3}\right) = -\frac{4}{3} + \frac{2}{3} = -\frac{2}{3}$$ $$x = -\frac{2}{3} \cdot \frac{5}{23} = -\frac{10}{69}$$ * При $y = 5$: $$\frac{23}{5}x = -\frac{4}{3} - 5 = -\frac{19}{3}$$ $$x = -\frac{19}{3} \cdot \frac{5}{23} = -\frac{95}{69} = -1\frac{26}{69}$$