1
x+y=a,xy=b
{a-b=-2⇒a=b+2
{ab=48
b²+2b-48=0
b1+b2=-2 U b1*b2=-48
b1=-8⇒a1=-6
b2=6⇒a2=8
1)a=-6,b1=-8
{x+y=-6⇒x=-6-y
{xy=-8
-y²-6y=-8
y²+6y-8=0
D=36+32=68
y1=(-6-2√17)/2=-3-√17⇒x1=-3+√17
y2=-3+√17⇒x1=-3-√17
2)a=8,b=6
{x+y=8⇒x=8-y
[xy=6
8y-y²=6
y²-8y+6=0
D=64-24=40
y1=(8-2√10)/2=4-√10⇒x1=4+√10
y2=4+√10⇒x2=4-√10
2
3y-x=14
x=3y-14
(3y-14)²-y(3y-14)+y-16=0
9y²-84y+196-3y²+14y+y-16=0
6y²-69y+180=0
2y²-23y+60=0
D=529-480=49
y1=(23-7)/4=4⇒x1=12-14=-2
y2=(23+7)/4=7,5⇒x2=22,5-14=8,5