Question

Aflați doua numere suma cărora eate -1/2 iar produsul tot -1/2

Answer 1

a+b=-1/2

ab=-1/2=》a=-1/2b

si inlocuim in suma

-1/2b +b=-1/2

-1+2b^2=-b

2b^2+b-1=0

delta=1-4×2×(-1)

delta=9=3^2

b1=(-1-3)/4=-4/4=-1

b2=(-1+3)/4=2/4=1/2

a1=-1/2×(-1)=-1/(-2)=1/2

a2=-1/(2×1/2)=-1

deci avem 2 perechi de nr (1/2 ; -1) si (-1 ; 1/2)