A
x²+6x-2-35/(x²+6x)=0
x²+6x=a
a-2-35/a=0
a²-2a-35=0,a≠0
a1+a2=2 U a1*a2=-35
a1=-5 U a2=7
x²+6x=-5
x²+6x+5=0
x1+x2=-6 U x1*x2=5
x1=-5 U x2=-1
x²+6x=7
x²+6x-7=0
x1+x2=-6 U x1*x2=-7
x1=-7 x2=1
Ответ x={-7;-5;-1;1}
2
(x²-x+1)/(x²+3x+5)+(x²+3x+5)/(x²-x+1)=2
(x²-x+1)/(x²+3x+5)=a
a+1/a=2
a²-2a+1=0,a≠0
(a-1)²=0
a-1=0
a=-1
(x²-x+1)/(x²+3x+5)=1
x²+3x+5=x²-x+1
x²+3x-x²+x=1-5
4x=-4
x=-1