Question

Gasiti a, b apartin lui R , stiind ca {x apartine lui R divide x^2 + ax+ b=0} = {1,2}

Answer 1

x are valorile 1 si 3
daca x=1
1²+1a+b=0⇒ 1+a+b=0⇒ a+b=-1
daca x=2
2²+2a+b=0⇒ 4+2a+b=0⇒ 2a+b=-4
scadem cele 2 ecuatii 
2a+b-a-b=-4+1⇒ a=-3
-3+b=-1⇒ b=-1+3=2⇒ b=2