Fie a si b cele doua numere, atunci:
a+b=125
a)
a=b+5
a+b=125 <=>
b+5+b=125 <=>
2b+5=125 <=>
2b=120 <=>
b=60 <=>
a=60+5 <=>
a=65
b)
a=3b+5
3b+5+b=125<=>
4b+5=125 <=>
4b=120 <=>
b=30 <=>
a=3*30+5 <=>
a=95
c)
a=2b-4
2b-4+b=125<=>
3b-4=125<=>
3b=129<=>
b=43=>
a=2*43-4<=>
a=82
d)
a-b=35<=>
a=b+35
b+35+b=125<=>
2b+35=125<=>
2b=90<=>
b=45=>
a=45+35<=>
a=80