25 вар
решите система уравнений
xy = -5
x^2 + y^2 = 26

X=5/y25/y² + y²=26y^4-26y²+25=0y²=aa²-26a+25=0a1+a2=26 U a1*a2=25a1=1⇒y²=1y1=-1⇒x1=-5y2=1⇒x2=5a2=25⇒y²=25y3=-5⇒x3=-1y4=5⇒x4=1

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