1)-1.4x+8.4=28х+8.4
-1.4х-28х=8.4-8.4
-29.4х=0
х=0:(-29.4)
х=0
2)1.04х-3.64=-4.68х+3.51
1.04х+4.68х=3.51+3.64
5.72х=7.15
х=7.15:5.72
х=1.25
3)6(5х+6)=5(2х+3.2)
30х+36=10х+16
30х-10х=16-36
20х=-20
х=-20:20
х=1
4) 3(х-8)=7(х+2)
3х-24=7х+14
3х-7х=14+24
-4х=38
х=38:(-4)
х=-9.5