Respuesta :
Answer:
See below.
Step-by-step explanation:
Compare our equation with one standard form of a circle:
x^2 + y^2 = r^2 where r = the radius.
So x^2 + y^2 = 9 is the equation of a circle with it's center at the origin and it's radius is 3 units.
x^2 + y^2 = 0 is not a circle because r = 0 ( a radius of 0). A circle of radius 0 is really a point!!
The value of the radius of a circle must be positive so it cannot have a radius of -3.
Answer
[tex]x ^{2} + {y}^{2} = r^{2} [/tex]
since all the terms are squared so there can be a negative number
but in number line
...... -4,-3,-2,-1,0,1,2,3.......
as we know negative sign indicates only the direction so -3 means in which coordinates will it lie.
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[tex] {x}^{2} + {y}^{2} = 9[/tex]
it means the origin is (0,0) and radius 3
