Question

Решите систему уравнений

Answer 1

1
x=7+y
(7+y)*y=-10
y²+7y+10=0
y1+y2=-7 U y1*y2=10
y1=-5⇒x1=7-5=2
y2=-2⇒x2=7-2=5
(2;-5);(5;-2)
2
x=1-2y
2-4y+y²+1=0
y²-4y+3=0
y1+y2=4 U y1*y2=3
y1=1⇒x1=1-2=-1
y2=3⇒x2=1-6=-5
(-1;1);(-5;3)
3
4xy=8
xy=2
y=2/x
x∈(-∞;0) U (0;∞)
y∈(-∞;0) U (0;∞)