2.
1-4х=2х+4+12х-3
1-4х=14х+1
14х+4х=1-1
18х=0
х=0÷18
х=0
3.
(-1/10+3/7-7/10)×35/6
=-----------------------------------=
-25/100
(-7/70+30/70-49/70)×35/6
=-----------------------------------------=
-1/4
-26/70×35/6
=-------------------=
-1/4
-13/35×35/6
=----------------=
-1/4
=-13/6 ÷(-1/4)=13/6×4/1=26/3=8 2/3