Question

rezolvati sistemul de ecuatii $\left \{ {{x+y=5} \atop {xy=6}} \right.$

Answer 1

x+y=5;
x·y=6⇒x,y∈[[1,6],[2,3],[3,2],[6,1]];
⇒x+y=5⇒x,y∈[[2,3],[3,2];
⇒x=2 sau 3;
⇒y=3 sau 2;

Answer 2

x=5-y
(5-y)y=6
5y-y²=6
y²-5y+6=0
y²-3y-2y+6=0
y(y-3)-2(y-3)=0
(y-3)(y-2)=0
y=3  ⇒ x=2
y=2  ⇒ x=3