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Select all of the points that lie on the circle with equation?​

Select all of the points that lie on the circle with equation?​-example-1
User Mikeesouth
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1 Answer

15 votes
15 votes

The easiest way to determine whether the point is on the circle:

plugging the values into the equation

⇒ then see if the equation holds true

⇒ meaning that the point is on the line

  • (3,-7)


(3-3)^2+(-7+2)^2=25\\(-5)^2=25\\25=25<== true

  • (8,-2)


(8-3)^2+(-2+2)^2=25\\5^2=25\\25=25<== true

  • (3,-3)


(3-3)^2+(-3+2)^2=25\\(-1)^2=25\\1=25<== false

  • (3,3)


(3-3)^2+(3+2)^2=25\\5^2=25\\25=25<== true

  • (-2,8)


(-2-3)^2+(8+2)^2=25\\(-5)^2+10^2\\25+100=25\\125=25<== false

Answer: (3,-7), (8,-2), (3,3)

Hope that helps!

User LouisChiffre
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3.4k points