Question

помогите пажалуйста 7класс надо всё расписать дам 50 баллов
срочно
срочно!!!!​

Answer 1

Ответ:

1)

$4(8 - y) = 0.2(5 - 0.5y) + 3.7$

$32 - 4y = 1 - 0.1y + 3.7$

$- 4y + 0.1y = - 32 + 1 + 3.7$

$- 3.9y = - 27.3$

$y = 7$

2)

$3(x - 2) = \frac{3}{4} (5 - 4x) - 0.15$

$3x - 6 = \frac{15}{4} - 3x - 0.15$

$3x + 3x = \frac{15}{4} + 6 - 0.15$

$6x = \frac{15}{4} + \frac{24}{4} - \frac{3}{20}$

$6x = \frac{192}{20}$

$x = \frac{192}{120}$

$6x = \frac{75 + 120 - 3}{20}$

$\times = \frac{192}{120}$

3)

$0.1 + 2(x + 5) = 3x - 5$

$0.1 + 2x + 10 = 3x - 5$

$2x - 3x = - 5 - 0.1 - 10$

$5x = - 15.1$

$x = - 5.02$

4)

$6.7 x+ \frac{4}{5} x = \frac{2}{3} (x - 20.5)$

$6.7x+ 0.8x = 2.3x - \frac{410}{30}$

$7.5x - 2.3x = \frac{410}{30}$

$5.2x = \frac{410}{30}$

$x = \frac{410}{30} \times \frac{10}{52}$

$x = \frac{410}{156} = \frac{205}{78}$

1)

$\frac{x + 5}{4} - 7 = \frac{7x - 3}{6}$

$\frac{x + 5 - 28}{4} - \frac{7x - 3}{6} = 0$

$\frac{3(x - 23) - 2(7x - 3)}{12} = 0$

$\frac{3x - 69 - 14x + 6}{12} = 0$

$\frac{ - 11x - 63}{12} = 0$

$- 11x - 63 = 0$

$- 11x = 63$

$x = - \frac{63}{11}$

3)

$\frac{7y + 1}{3} - \frac{y + 1}{4} = \frac{5y - 19}{12}$

$\frac{4(7y + 1) - 3(y + 1)(5y - 19)}{12} = 0$

$28y + 4 - 3y - 3 - 5y - 19 = 0$

$20y = 18$

$y = \frac{18}{20} = 0.9$

4)

$\frac{x - 3}{6} + \frac{2x + 5}{3} = \frac{2x - 6}{9}$

$\frac{3(x - 3) + 6(2x + 5) - 2(2x - 6)}{18} = 0$

$3x - 9 + 12x + 30 - 4x + 12 = 0$

$11x = - 33$

$x = - 3$