Решите уравнение: -5 7-(м-1)=11 14

5/7-(m-1)=11/14 -4/7-m+1=11/14 -m=11/14+4/7-1 -m=(11+8-14)/14=5/14 m=-5/14

5х - 2у = 7   |*2     __> >   (10х - 4у = 14   > > (13х = 39 (3х + 4у = 25                 + (3х + 4у = 25                 х = 3    а теперь найдем  у:     5 * 3 - 2у = 715 - 2у = 7-2у = 7 - 15-2у = -8у = -8 : (-2) у = 4                              ответ:   х = 3,  у = 4      а теперь проверь сам!

1) 3/7 + 5/14 = 6/14 + 5/14 = 11/14

2) 2 1/8 + 3 5/12 = 2 3/24 + 3 10/24 = 5 13/24

3) 6 15/21 + 2 9/14 = 6 30/42 + 2 27/42 = 8 57/42 = 9 15/42 = 9 5/14

4) 5 13/15 + 1 7/12 = 5 52/60 + 1 35/60 = 6 87/60 = 7 27/60 = 7 9/20

5) 1 - 9/11 = 11/11 - 9/11 = 2/11

6) 8/9 - 7/12 = 32/36 - 21/36 = 11/36

7) 8 - 5 4/9 = 7 9/9 - 5 4/9 = 2 5/9

8) 7 3/8 - 3 5/6 = 7 9/24 - 3 20/24 = 6 33/24 - 3 20/24 = 3 13/24 = 3 13/24

9) 3/8 * 2/9 = 6/72 =  1/12

10) 2 1/10 * 1 1/14 = 21/10 * 15/14 = 9/4 = 2 1/4

11) 3 2/5 * 1/19 = 17/5 * 1/19 = 17/95

12) 5/7 : 3/8 = 5/7 * 8/3 = 40/21 = 1 19/21

13) 4 4/9 : 2 2/3 = 40/9 : 8/3 = 40/9 * 3/8 = 5/3 = 1 2/3