№ 1)
х+12 = 3х
3х-х=12
2х=12
х=6
№ 2)
-7-х = 3х+17
3х+х=-7-17
4х=-24
х=-6
№ 3)
(х+1)+2(х+1)+3(х-1) < 4х+3(х-2)
х+1+2х+2+3х-3<4х+3х-6
х+1+2х+2+3х-3-4х-3х+6<0
-х+6<0
x-6>0
x>6
№ 1)
х+12 = 3х
3х-х=12
2х=12
х=6
№ 2)
-7-х = 3х+17
3х+х=-7-17
4х=-24
х=-6
№ 3)
(х+1)+2(х+1)+3(х-1) < 4х+3(х-2)
х+1+2х+2+3х-3<4х+3х-6
х+1+2х+2+3х-3-4х-3х+6<0
-х+6<0
x-6>0
x>6