Question

решите систему уравнений.
3х-у=5
3х^2+у^2=13

Answer 1

$\left \{ {{y=3x-5} \atop {12 x^{2}-30x+12=0}} \right.$
$12 x^{2} -30x+12=0$
$2 x^{2} -5x+2=0$
$D=25-16=9; \sqrt{D} =3;$
$x_{1} =(5+3)/2=8/2=4$
$x_{2}=(5-3)/2=2/2=1$
$y_{1} =12-5=7$
$y_{2}=3-5=-2$
(4;7) (1;-2)