2)

5х+12=8х+30

5х+12-8х-30=0

-3х-18=0

-3х=18

х=18/(-3)

х=-6

4)

6х-19=-х-10

6х-19+х+10=0

7х-9=0

7х=9

х=9/7

6)

0,1х+9=0,2х-4

0,1х+9-0,2х+4=0

-0,1х+13=0

-0,1х=-13

х=-13/(-0,1)

х=130.

5x + 12 = 8x + 30;

5x - 8x = -12 + 30;

-3x = 18;

x = 18 : (-3);

x= -6

6x - 19 = -x - 10;

6x + x = 19 - 10;

7x = 9;

x= 9/7

0,1x + 9 = 0,2 x - 4;

0,1x-0,2x=-9-4;

-0,1x=-13;

x=130