Помогите пожалуста!!!

Ответ:

7. 6к+9к+10к=100

25к=100

к=4

Сторони: 24 см, 36 см, 40 см

8. 1) x = 5*91/7 = 65

2) 3x-7 = 10*4/5 = 8

9. x/y = 4/3 => 3x = 4y => y = 3x/4

y/z = 2/5 => 5y = 2z => z = 5y/2 = 15x/8

x+y+z = 145

x + 3x/4 + 15x/8 = 145

8x/8 + 6x/8 + 15x/8 = 145

29x/8 = 145

x = 145*8/29 = 40

y = 3*40/4 = 30

z = 15*40/8 = 75

ПРОВЕРКА: x/y = 40/30 = 4/3

y/z = 30/75 = 2/5

40+30+75 = 145