1.
The equation of a circle is 3
x
2
+ 3
y
2
– 6
x
+ 12
y
– 24 = 0. Write the standard form of the equation.
A.
B.
(
x
– 1)
2
+ (
y
– 2)
2
= 13
C.
D.
(
x
– 1)
2
+ (
y
+ 2)
2
= 13
Hint
2.
The equation of a circle is 3
x
2
+ 3
y
2
– 6
x
+ 12
y
– 24 = 0. Find its center and radius.
A.
(–1, 2); 13
B.
(–1, 2);
C.
(1, –2); 13
D.
(1, –2);
Hint
3.
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
= 13
C.
(
x
– 3)
2
+ (
y
+ 2)
2
= 10
D.
(
x
+ 3)
2
+ (
y
+ 2)
2
= 5
Hint
4.
Write the equation of the circle whose diameter has endpoints at (3, –1) and (–9, 5).
A.
(
x
+ 3)
2
+ (
y
– 2)
2
= 13
B.
(
x
+ 3)
2
+ (
y
– 2)
2
= 45
C.
(
x
– 3)
2
+ (
y
+ 2)
2
= 45
D.
(
x
– 3)
2
+ (
y
+ 2)
2
= 13
Hint
5.
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.
B.
(
x
– 4)
2
+ (
y
+ 1)
2
= 18
C.
(
x
+ 4)
2
+ (
y
– 1)
2
= 18
D.
Hint