Question

a + b = 39
a - b = 15

Aflati a si b .

Answer 1

a+b=39 a-b=15
a=15+b
15+b+b=39
15+2b=39
2b=39-15
2b=24
b=24/2
b=12
a=15+12
a=27
verificare
a+b=39
27+12=39
27-12=15

Answer 2

A + b = 39
A - b = 15              ( Le adunam)
2A / = 54
A = 27

(Schimbam A in prima )
A + b = 39
27 + b = 39
b = 12