Răspuns :
a-b= 28
( a+b)- (a-b) = 42
a+b-28+42
a+b = 42+28
28+b+b= 70
b= 21
a= 49
( a+b)- (a-b) = 42
a+b-28+42
a+b = 42+28
28+b+b= 70
b= 21
a= 49
a-b=28
(a+b)-28=42
a=28+b
(28+b+b)-28=42
28+2b=42+28
28+2b=70
2b=70-28
2b=42
b=42:2
b=21
numerele sunt : 49 si 21 49-21=28 si 49+21-28=42
(a+b)-28=42
a=28+b
(28+b+b)-28=42
28+2b=42+28
28+2b=70
2b=70-28
2b=42
b=42:2
b=21
numerele sunt : 49 si 21 49-21=28 si 49+21-28=42