Răspuns :
(x+y)^2 = x^2+2xy+y^2
x^2+y^2 = (x+y)^2 - 2xy
Dar x+y = 4 si xy=3
=> x^2+y^2 = 4^2 - 6 = 16-6=10
x^2+y^2 = (x+y)^2 - 2xy
Dar x+y = 4 si xy=3
=> x^2+y^2 = 4^2 - 6 = 16-6=10