a/ (3x -12 ):8+10=13
<=>(3x-12):8=3
<=>3x-12=24
<=>3x=36
<=>x=12
b/(x+5)x8-20=60
<=>(x+5)x8=80
<=>x+5=80:8
<=>x+5=10
x=5
c/3x[35+(x-10)]-375=0
<=>3x[35+(x-10)]=375
<=>35+(x+10)=125
<=>x+10=90
x=80
d/(158x+173-24):35=81
<=>158x+173-24=2835
<=>158x+173=2859
<=>158x=2686
<=>x=17
e/x-140:35=0
<=>x-140=0
<=>x=140+0
x=140
a) ( 3x - 12 ) : 8 + 10 = 13
=> (3x - 12) : 8 = 3
=> 3x - 12 = 24
=> 3x = 12
=> x = 4
a) ( 3x - 12 ) : 8 + 10 = 13
=> (3x - 12) : 8 = 3
=> 3x - 12 = 24
=> 3x = 12
=> x = 4