Решите примеры:1) 4,5:(3х)=4:28;2)(2х):9=2целых1/3:5целых1/4;3) 1,25:0,4=1,35:(0,3х);4) 1целая1/5:1=(2х):2/3.

1) 4,5 : (3 * х) = 4 : 28;

4,5 : (3 * х) = 4/28;

3 * х = 4 5/10 : 4/28;

3 * х = 9/2 : 1/7;

3 * х = 9/2 * 7/1;

3 * х = 63/2;

х = 63/2 : 3;

х = 63/2 * 1/3;

х = 63/6;

х = 10 1/2.

Проверка:

4,5 : (3 * 10,5) = 4 : 28;

4,5 : 31,5 = 4/28;

45/10 : 315/10 = 4/28;

45/10 : 63/2 = 4/28;

45/10 * 2/63 = 4/28;

9/2 * 2/63 = 4/28;

18/126 = 4/28;

9/63 = 2/14;

1/7 = 1/7. Решение верно.

2) (2 * х) : 9 = 2 1/3 : 5 1/4;

(2 * х) : 9 = 7/3 : 21/4;

(2 * х) : 9 = 7/3 * 4/21;

(2 * х) : 9 = 4/9;

2 * х = 4/9 * 9;

2 * х = 4;

х = 2.

Проверка:

(2 * 2) : 9 = 2 1/3 : 5 1/4;

4 : 9 = 7/3 : 21/4;

4/ 9 = 7/3 * 4/21;

4/9 = 4/9. Решение верно.

3) 1,25 : 0,4 = 1,35 : (0,3 * х);

3,125 = 1,35 : (0,3 * х);

0,3 * х = 1,35 : 3,125;

0,3 * х = 0,432;

х = 0.432 : 0,3;

х = 1,44

Проверка:

1,25 : 0,4 = 1,35 : (0,3 * 1,44);

3,125 = 1,35 : 0,432;

3,125 = 3,125. Решение верно.

4) 1 1/5 : 1 = (2 * х) : 2/3;

6/5 : 1 = (2 * х) : 2/3;

6/5 = (2 * х) : 2/3;

2 * х = 2/3 * 6/5;

2 * х = 12/15;

х = 4/5 : 2;

х = 4/5 * 1/2;

х = 4/10 = 2/5.

Проверка:

1 1/5 : 1 = (2 * 4/10) : 2/3;

6/5 : 1 = 8/10: 2/3;

6/5 = 8 * 3/20;

6/5 = 24/20;

6/5 = 6/5. Решение верно.