X=8-y
8(8-y)=-20
-y^2+8x+20=0
D=64+80=144 больше 0 - 2 корня
y1= -8+12/2=-2
y2= -8-12/-2=10
(x-1)²*[(x²-3)-(5-2x)]≥0
(x-1)*(x²-3-5+2x)≥0
(x-1)²(x²+2x-8)≥0
x-1=0⇒x=1
x²+2x-8=0
x1=x2=-2 U x1*x2=-8⇒x1=-4 U x2=2
+ _ _ +
-----------------[-4]---------------[1]---------------[2]--------------------
x∈(-∞;-4] U {1} U [2;∞)
|x|<7
-6-5-4+1+2+3+4+5+6=6
1)=1*1/2*(-1/2)=-1/4
2)=ctg(-5p/4)*1/2*sin(3p/2)=-1*1/2*(-1)=1/2
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