Răspuns :
a+b=47(1)
a-b=27(2)
din relatia 1 rezulta ca a=47-b
inlocuim in rel.2
47-b-b=27
47-2b=27
-2b=27-47
b=10
a=47-10
a=37
a-b=27(2)
din relatia 1 rezulta ca a=47-b
inlocuim in rel.2
47-b-b=27
47-2b=27
-2b=27-47
b=10
a=47-10
a=37
a+b=47
a-b=27
a=47-b
47-b-b=27
47-27=b+b
20=2b
b=20:2=10
a=47-10=37
sau:
le adunam
a+b+a-b=47+27
2a=74
a=74:2=37
a=47-37=10
prin doua metode
a-b=27
a=47-b
47-b-b=27
47-27=b+b
20=2b
b=20:2=10
a=47-10=37
sau:
le adunam
a+b+a-b=47+27
2a=74
a=74:2=37
a=47-37=10
prin doua metode