Question

Помогите пожалуйста решить 7,8,9,10 нечего не понимаю

Answer 1

Ответ:

7)

$5 frac{5}{6} div 3 frac{1}{2} = x div 15$

$frac{35}{6} div frac{7}{2} = x div 15$

$frac{35}{6} times frac{2}{7} = frac{x}{15}$

$frac{5}{3} = frac{x}{15}$

$3x = 75$

$x = 25$

8)

$frac{4}{5} x + 6(3 - frac{2}{5} x) = 17$

$frac{4}{5} x + 18 - frac{12}{5} x = 17$

$frac{4}{5} x - frac{12}{5} x = 17 - 18$

$x = 1 times frac{5}{8}$

$x = frac{5}{8}$

9)

$5(x - 7) = 3(x - 4) - 27$

$5x - 35 = 3x - 12 - 27$

$5x - 3x = - 12 - 27 + 35$

$2x = - 4$

$x = - 2$

10)

$frac{x - 0.8}{x + 0.2} = frac{6.3}{7.3}$

$- 0.8 times 7.3 = 0.2 times 6.3$

$- 5.84 = 1.26$

$x = 1.26 + 5.84 = 7.1$