Răspuns :
Fie a si b numerele, atunci:
(a+b)+(a-b)=60
a+b+a-b=60
2a=60
a=60:2
a=30
(a+b)-(a-b)=40
a+b-a+b=40
2b=40
b=40:2
b=20
(a+b)+(a-b)=60
a+b+a-b=60
2a=60
a=60:2
a=30
(a+b)-(a-b)=40
a+b-a+b=40
2b=40
b=40:2
b=20
I nr - x
II nr- y
x+y+(x-y)=60 (x+y)-(x-y)=40
x+y+x-y=60 x+y-x+y=40
2x=60 2y=40
x=30 y=20
II nr- y
x+y+(x-y)=60 (x+y)-(x-y)=40
x+y+x-y=60 x+y-x+y=40
2x=60 2y=40
x=30 y=20