Răspuns:
Explicație:
a) a+b=2019
a-b=471=>a= b+471
b+471+b=2019
2*b=2019-471
2*b=1548
b=774
a=774+471=1245
b)a+b=2020
a=b+806
b+806+b=2020
2*b=2020-806
2*b=1214
b=607
a=607+806=1413
c)a+b=2021
b=a+27
a+a+27=2021
2*a=2021-27
2*a=1994
a=997
b=997+27=1024