Circle A has an equation of (x + 8)squared + (y + 3)squared = 16. Where is the center of the circle located?

in the first quadrant

on the y-axis

on the x-axis

in the third quadrant

Question

Circle A has an equation of (x + 8)squared + (y + 3)squared = 16. Where is the center of the circle located?

 in the first quadrant

 on the y-axis

 on the x-axis

 in the third quadrant

eyust707 · Answer

okay so now they have taken it a step further

eyust707 · Answer

You know to find the center and you know how to find the radius. This time they give you an equation that tells you information about the center and information about the radius.

eyust707 · Answer

The standard equation of a circle is as follows:
$$(x-h)^2 +(y-k)^2 = r ^2 $$

eyust707 · Answer

The r represents the radius.
The h represents the x-value of the center
The k represents the y-value of the center

eyust707 · Answer

The x and y just stay as x and y.

eyust707 · Answer

You understand that so far?

anonymous · Answer

trying to but continue

eyust707 · Answer

So your equation is:
$$(x+8)^2 + (y+3)^2 = 16$$

eyust707 · Answer

Look at the standard equation, what would you have to put in for h to get it to look like yours?

anonymous · Answer

ok i think you have completely lost me :-(

eyust707 · Answer

$$(x-h)^2 +(y-k)^2 = r ^2$$
$$(x+8)^2 + (y+3)^2 = 16$$

eyust707 · Answer

look at the botttom equation

eyust707 · Answer

what number is in the place of "h"

anonymous · Answer

8

eyust707 · Answer

-8

anonymous · Answer

oh

anonymous · Answer

center , -8,-3

eyust707 · Answer

-8 is the x value of the center

anonymous · Answer

but (-8,-3) are not first quadrant

anonymous · Answer

oh is -8-3 in the third quadrant?

eyust707 · Answer

yes... sam ruined it...

eyust707 · Answer

lol

anonymous · Answer

lol

anonymous · Answer

lol

anonymous · Answer

well i have another question that you can help me with

eyust707 · Answer

sure post it

eyust707 · Answer

you can just put it here if you want

anonymous · Answer

A circle is shown on the coordinate plane below.
 
  
 
What is the equation of this circle?

 (x – 1)2 + y2 = 2

 (x + 1)2 + y2 = 4

 (x + 1)2 + y2 = 2

 (x – 1)2 + y2 = 4

anonymous · Answer

attachment

eyust707 · Answer

Whats the radius of the circle shown?

anonymous · Answer

2?

eyust707 · Answer

Yep! and the center?

anonymous · Answer

0,1?

eyust707 · Answer

the x value always comes first...

eyust707 · Answer

(1,0)

anonymous · Answer

lol

anonymous · Answer

ok

eyust707 · Answer

So:
r=2
center= (1,0)
That means 
h= 1
k = 0

eyust707 · Answer

Now just plug r h and k into the standard equation.
$$(x-h)^2 +(y-k)^2 = r ^2$$

anonymous · Answer

lol don't worry sam isn't gonna ruin this 1

anonymous · Answer

lol sam

anonymous · Answer

so r is 2 and h is -1?

eyust707 · Answer

be careful when you plug in
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