+164 The equation of a circle is x2+4x+y2−10y+13=0 .
What is the equation of the circle in standard form?
A.) (x+2)2+(y−5)2=25
B.) (x+4)2+(y−25)2=25
C.) (x+2)2+(y−5)2=16
D.) (x+4)2+(y−25)2=16
+9479 x2 + 4x + y2 - 10y + 13 = 0
Subtract 13 from both sides of the equation.
x2 + 4x + y2 - 10y = -13
Add (4/2)2 , or 4, and (10/2)2 , or 25, to both sides of the equation.
x2 + 4x + 4 + y2 - 10y + 25 = -13 + 4 + 25
Now we can factor the x part and y part like this....
(x + 2)2 + (y - 5)2 = 16
