Răspuns:
1)a+b=25
a-b=5
a=5+b
5+b+b=25
2b=20
b=10
a=15
2)a+b=54
a=18+b
18+b+b=54
2b=36
b=18
a=36
3)a+b=49
a=b-17
b-17+b=49
2b=66
b=33
a=16
4)a+b=58
a=14+b
14+b+b=58
2b=44
b=22
a=36
5)a+b=26
a=4+b
4+b+b=26
2b=22
b=11
a=15
5)a+b=100
a=b+24
b+24+b=100
2b=76
b=38
a=38+24=62