Question

Here is the equation of a circle in standard form.

(x + 10)2 + (y + 9)2 = 100

What are the coordinates of the center?

A. (-10, -9)
B. (9, 10)
C. (-9, -10)

Answer 1

A

Explanation:

The equation of a circle in standard form is:
`(x-h)^2+(y-k)^2=r^2`, where (h, k) is the center and r is the radius.

Here, our equation is:
`(x+10)^2+(y+9)^2=100` , which means that h = -10 and k = -9. Then, the center is (-10, -9).

The answer is A.

Answer 2

A

Explanation:

The equation is in the standard form of a circle:

(x – h)^2 + (y – k)^2 = r^2

where (h,k) is the center, and r is the radius.

If we compare the 2 equations:

(x – h)^2 + (y – k)^2 = r^2

(x + 10)^2 + (y + 9)^2 = 100

We can see that the center is (-10, -9).

This is because (x- -10) will become (x+10), and (y- -9) will become (x+9).

So, choice A is correct