Răspuns:
2021 = 47×43
47+43=90
⇒ x = 47×90 = 4230
y = 43×90 = 3870
verificare:
1/x+1/y = 1/(47×90) + 1/(43×90) = (43+47)/(43×47×90) = 90/(43×47×90) = 1/(43×47) = 1/2021
