Найдите неизвестный член пропорции (75) 75. 1) x: 20 = 2: 5; 3) x:18 = 2:3; 5) 5:9 = 15:х; 2) x:18 = 7 : 9; 4) 6:х = 3:7;​

Пошаговое объяснение:

1) x: 20 = 2: 5;

5*x = 20*2

5x = 40

x = 40 : 5

x = 8

3) x:18 = 2:3;

3*x = 18*2

3x = 36

x = 36 : 3

x = 12

5) 5:9 = 15:х;

5*x  = 15*9

5x = 135

x = 135 : 5

x = 27

2) x:18 = 7 : 9;

9*x = 18*7

9x = 126

x = 126 : 9

x = 14

4) 6:х= 3:7;​

3*x = 7*6

3x = 42

x = 42 : 3

x = 14