

1. 
The equation of a circle is 3x^{2} + 3y^{2} – 6x + 12y – 24 = 0. Find its center and radius. 


A. 
(–1, 2); 13 
B. 
(–1, 2); 


C. 
(1, –2); 
D. 
(1, –2); 13 


Hint 


2. 
Write the equation of a circle that passes through the origin and has its center at (–3, –2). 


A. 
(x + 3)^{2} + (y + 2)^{2} = 13 


B. 
(x – 3)^{2} + (y + 2)^{2} = 10 


C. 
(x + 3)^{2} + (y + 2)^{2} = 5 


D. 
(x – 3)^{2} + (y – 2)^{2} = 13 


Hint 


3. 
Write the equation of the circle that is tangent to the line with equation x + y = –3 and has its center at (4, –1). 


A. 
(x + 4)^{2} + (y – 1)^{2} = 18 
B. 
(x – 4)^{2} + (y + 1)^{2} = 18 


C. 

D. 



Hint 


4. 
Write the equation of a circle that passes through points (1, 2), (1, 4) and (3, 2) in standard form. 


A. 
(x  1) ^{2} + (y  2) ^{2} = 4 


B. 
(x  1) ^{2} + (y + 3) ^{2} = 4 


C. 
(x + 1) ^{2} + (y  3) ^{2} = 4 


D. 
(x + 1)^{2} + (y  2) ^{2} = 4 


Hint 


5. 
Write the equation of a circle that has a diameter with endpoints at (1, 0) and (5, 4). 


A. 
(x  3) ^{2} + (y  2) ^{2} = 8 


B. 
(x + 3) ^{2} + (y  2) ^{2} = 64 


C. 
(x  3) ^{2} + (y  2) ^{2} = 64 


D. 
(x + 3) ^{2} + (y + 2) ^{2} = 8 


Hint 

