Sin(-x/2)=1/2
x/2=(-1)^(n+1)*pi/6+pin
X=2(-1)^(n+1)*pi/3+2pin
х^3-2x^2-9x+18=0
x^2(x-2)-9(x-2)=0
(X^2-9)*(x-2)=0
x^2=9 x=2
x=3 x=-3
Ответ: х=3, х=-3, х=2
{x²+2x-9y²-6y=0⇒(x+1)²-(3y+1)²=0
{5x+6y+1=0
(x+1)²-(3y+1)²=0
(x+1)²=(3y+1)²
1)x+1=-3y-1
x=-3y-2
5(-3y-2)+6y+1=0
-15y-10+6y+1=0
-9y=9
y=-1
x=3-2=1
2)x+1=3y+1
x=3y
15y+6y+1=0
21y=-1
y=-1/21
x=-1/7
Ответ (1;-1);(-1/7;-1/21)
Во вложении
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