# SOLUTION: HELP PLEASE x^+10x+y^-6y+9=0 represents a circle. find radius and centre. also find any point an circle that intersects line y=-x+3 any assistance would be greatly appreciated.

Algebra ->  Algebra  -> Circles -> SOLUTION: HELP PLEASE x^+10x+y^-6y+9=0 represents a circle. find radius and centre. also find any point an circle that intersects line y=-x+3 any assistance would be greatly appreciated.      Log On

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 Geometry: Circles and their properties Solvers Lessons Answers archive Quiz In Depth

 Click here to see ALL problems on Circles Question 184708: HELP PLEASE x^+10x+y^-6y+9=0 represents a circle. find radius and centre. also find any point an circle that intersects line y=-x+3 any assistance would be greatly appreciated.Answer by stanbon(57222)   (Show Source): You can put this solution on YOUR website!x^2+10x+y^2-6y+9=0 represents a circle. find radius and centre. also find any point an circle that intersects line y=-x+3 ---------------- Complete the square on the x-terms and on the y-terms, as follows: x^2 + 10x + ? + y^2 -6y + ? = -9 + ?+? x^2 + 10x + 25 + y^2 - 6y + 9 = -9 + 25 + 9 (x+5)^2 + (y-3)^2 = 25 --------------------------- center is (-5,3) radius = sqrt(25) = 5 =========================== Find any point on the circle that intersects line y=-x+3 ----------- Substitute for "y" in the circle equation to solve for "x". (x+5)^2 + (-x+3-3)^2 = 25 x^2 + 10x + 25 + x^2 = 25 2x^2 + 10x = 0 2x(x+5) = 0 x = 0 or x = -5 -------------------- Usiing y = -x+3, for the y-values that correspond to x = 0 and to x=-5: If x=0, y = 3 If x = -5, y = 8 ======================= Intersection points are (0,3) and (-5,8) ============================================ Cheers, Stan H.