First, you try to make sure that both the denominators are the same. In order to do this, you multiply both fractions' numerator and denominator by the other fraction's denominator. Next, you combine like terms in the numerator, and then you simplify the fraction.
Answer:
A) 
Step-by-step explanation:
The equation of a circle is
where
is the center and
is the radius. If
and
, then:

Therefore, the equation of the circle is 