Question

№ 1)  х+12 = 3х 

№ 2)  -7-х = 3х+17 

№ 3)  (х+1)+2(х+1)+3(х-1) < 4х+3(х-2)

Answer 1

№ 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