Răspuns :
2a+2b=10
2a=10-2b
2a/2=10/2-2b/2
a=5-b
a=5-b,b apartine R
3a-3b=12
3a-3b+3b=12+3b
3a=12+3b
3a/3=12/3+3b/3
a=4+b
a=4+b,b apartine R
2a=10-2b
2a/2=10/2-2b/2
a=5-b
a=5-b,b apartine R
3a-3b=12
3a-3b+3b=12+3b
3a=12+3b
3a/3=12/3+3b/3
a=4+b
a=4+b,b apartine R