Ответы и объяснения

2013-04-23T18:18:53+00:00

3 Вариант:

1. а) -7х=5           б) 4х=0                        в)  0*х=4

         х=-5/7                х=0:4=0                       х=4:0- не имеет решения ,, на 0 делить нельзя

 

2. а) 5х-12=2х+11                               б) 5х+7=2х-3

         5х-2х=11+12                                    5х-2х=-3-7

         3х=23                                                 3х=-10

          х=23:3                                                х=-10:3

          х=7,67 или 7 целых 2/3                 х=  - 3.33   или  - 3 целыз 1/3

 

в)5(2х-3)=3х+3                                               г) х-3(5х-4)=-10х+1

   10х-15=3х+3                                                    х-15х+12=-10х+1

    10х-3х=3+15                                                   -14х+10х=1-12

     7х=18                                                               -4х=-11

      х=18:7                                                               х=11/4=2,75 или 2 целых 3/4

     х= 2,57 или 2 целых 4/7

 

3.  а) 5(0,4х-0,8)=4(0,5х+1)                          б) 6(0.4х-0,5)-1,3х=1.1х-3

2х-4=2х+4                                                              2,4х-3-1,3х=1,1х-3

2х-2х=4+4                                                                2,4х-1,3х-1,1х=3-3

 не имеет решения                                               0=0