1
{x+y=-2 ⇒x=-y-2
{y^2-3x=6
y²+3y+6-6=0
y²+3y=0
y(y+3)=0
y=0⇒x=-2
y=-3⇒x=1
(-2;0);(1;-3)
2
{x^2+y^2=17
{y-x=3⇒y=3+x
x²+9+6x+x²-17=0
2x²+6x-8=0
x²+3x-4=0
x1+x2=-3 U x1*x2=-4
x1=-4⇒y1=-1
x2=1⇒y2=4
(-4;-1);(1;4)
3
{x-y=1 ⇒x=1+y
{x-4y^2=1
1+y-4y²-1=0
y-4y²=0
y(1-4y)=0
y=0⇒x=1
y=1/4⇒x=1 1/4
(1;0);(1 1/4;1/4)
4
{x+2y^2=4
{x-y=4
отнимем
2y²+y=0
y(2y+1)=0
y=0⇒x-0=4⇒x=4
y=-0,5⇒x+0,5=4⇒x=3,5
(4;0);(3,5;-0,5)