Решите уравнения 1) 2х= 4\3(х+15) 2) 2\3(10-х)=-12 3) -1\4(5х-7)=6 вот этим знаком \ я обозначила дробь

1) 2х = 4/3 * (х + 15)                      2) 2/3 * (10 - х) = - 12

2х = 4/3х + 4/3*15                          2/3*10 - 2/3х = - 12

2х - 1 1/3х = 20                               20/3 + 12 = 2/3х

2/3х = 20                                         18 2/3 = 2/3х

х = 20 : 2/3 = 20 * 3/2                     х = 56/3 : 2/3 = 56/3 * 3/2

х = 60/2 = 30                                  х = 168/6 = 28

3) - 1/4 * (5х - 7) = 6

- 1/4*5х - 1/4 * (- 7) = 6

- 5/4х + 7/4= 6 

- 1,25х = 6 - 1,75

- 1,25х = 4,25

х = 4,25 : (-1,25)

х = - 3,4

 

1)2х= 4\3(х+15)
2х-4/3х=20
2/3х=20
х=20:2/3=20*3/2=30
2)2\3(10-х)=-12
-2/3х=-12-20/3
-2/3х=-56/3
х=-56/3:(-2/3)=56/3*3/2=28
3) -1\4(5х-7)=6
-5/4х=6-7/4
-5/4х=17/4
х=17/4:(-5/4)=-17/4*4/5=-17/5=-3,4