Question 746357
How do I write an equation for a circle whose center is (3,-1) and radius is 2? 
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Which equation? the standard or the general equation?
In solving this problem, the standard equation is use: {{{(x-h)^2+(y-k)^2=r^2}}}
Center is (3,-1) so h = 3 and k = -1, r^2 = 4
{{{(x-3)^2+(y+1)^2=4}}}, this is the standard equation
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Simplifying, {{{(x^2-6x+9)+(y^2+2y+1)=4}}}
{{{x^2+y^2-6x+2y+6=0}}}, this is the general equation of the circle.