X²+y²+6x-14y-5 = 0
(x+3)²-9+(y-7)²-49-5 = 0
(x+3)²+(y-7)² = 63
O(-3;7), R=√63=3√7
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x²+y²+x = 0
(x+1/2)²-1/4+y² = 0
(x+1/2)²+y² = 1/4
O(-1/2;0), R=1/2
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x²+y²-18x+2y+50 = 0
(x-9)²-81+(y+1)²-1+50 = 0
(x-9)²+(y+1)² = 32
O(9;-1), R=4√2
r(OA) = √((9-5)²+(-1+1)²) = √(4²+0²) = 4 < R внутри круга
r(OB) = √((9-2)²+(-1-4)²) = √(7²+5²) = √74 > R вне круга
r(OС) = √((9-13)²+(-1+5)²) = √(4²+4²) = 4√2 = R на границе круга