5+(a+17)=125
a+17=125-5
a=120-17
a=103
proba
5+(103+17)=125
5+120=125
125=125
148-(2:a+5)=3
148-3=2:a+5
145-5=2:a
140=2:a
a=2/140=1/70
proba
148-(2:1/70+5)=3
148-(140+5)=3
148-145=3
3=3
[(a-2):98+79]:8=10
(a-2):98+79=80
(a-2):98=80-79
(a-2):98=1
a-2=98
a=100
proba
[(100-2):98+79]:8=10
(98:98+79):8=10
(1+79):8=10
80:8=10
10=10