Equations Of Circles Worksheets With Answers Page 6

ADVERTISEMENT

2
2
The equation of a circle is
x + y - 8x + 2y = -8
Write the equation in standard form.
Then state the coordinates of the center and the measure of the radius.
Step 1: Isolate and group like terms.
2
2
x + y - 8x + 2y = -8
2
2
x - 8x
+ y + 2y
= -8
Step 2: Complete the square for both sets of like terms.
Remember: to complete the square,
find half of b, then square that result.
Add that number to both sides of the equation
2
2
x - 8x
+ y + 2y
= -8
Step 3: Factor and simplify
2
2
+ 1
+ 1
x - 8x
+ y + 2y
= -8
+ 16
+ 16
(x - 4)(x - 4)
+
(y + 1)(y + 1)
= 9
2
2
(x - 4)
+
(y + 1)
= 9
The center is:
The measure of the radius is:

ADVERTISEMENT

00 votes

Related Articles

Related forms

Related Categories

Parent category: Education
Go
Page of 8