a) 2x+12=20 |-12
2x=8 |:2
x=4
b) 6x-5=25 |+5
6x=30 |:6
x=5
c) x/2+3=10 |-3
x/2=7 |•2
x=14
d) 2x+4=10x-2
2x-10x=-2-4
-8x=-6 |:(-8)
x=0,75
e) 8-2x/2=20 |•2
8-2x=40 |-8
-2x= 32 |:(-2)
x= -16
f) 3/4x-3+1/4x=10 |+3
x=13
