Răspuns:
3(x+7)=129
x+7=129/3
x=43-7
x=36
5(x+9)=175
x+9=175/5
x=35-9
x=26
18(x-11)=144
x-11=144/18
x=8+11
x=19
15(18-x)=180
18-x=180/15
x=18-12
x=6
63:(x-5)=7
x-5=63÷7
x=9+5
x=14
(x-4)÷15=16
x-4=16×15
x=240+4
x=244
14x+28x=588
42x=588
x=588÷42
x=14
156÷(2x+1)=52
2x+1=156÷52
2x=3-1
x=2÷2
x=1