Question

The equation of a circle is given below:

x squared minus 4 x plus y squared minus 6 y minus 7 equals 0

Identify the center and radius of the circle.

Group of answer choices

Center: left parenthesis 2 comma 3 right parenthesis
Radius: 20

Center: left parenthesis 4 comma minus 6 right parenthesis
Radius: 2 square root of 5

Center: left parenthesis negative 4 comma 6 right parenthesis
Radius: 20

Center: left parenthesis 2 comma 3 right parenthesis
Radius: 2 square root of 5

Answer 1

Given:

The equation of the circle is

We need to determine the center and radius of the circle.

Center:

The general form of the equation of the circle is

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

Let us compare the general form of the equation of the circle with the given equation to determine the center.

The given equation can be written as,

Comparing the two equations, we get;

(h,k) = (0,-4)

Therefore, the center of the circle is (0,-4)

Radius:

Let us compare the general form of the equation of the circle with the given equation to determine the radius.

Hence, the given equation can be written as,

Comparing the two equation, we get;

Thus, the radius of the circle is 8