Which of the following equations is represented by a graph that is centered at [tex]$(-6,-8)$[/tex] and includes the point [tex]$(0,-8)$[/tex]?

A. [tex]$(x-6)^2+(y-8)^2=6$[/tex]
B. [tex]$(x-6)^2+(y-8)^2=36$[/tex]
C. [tex]$(x+6)^2+(y+8)^2=6$[/tex]
D. [tex]$(x+6)^2+(y+8)^2=36$[/tex]



Answer :

Sure! Let's solve this step by step.

The general equation for a circle in the coordinate plane with the center [tex]\((h, k)\)[/tex] and radius [tex]\(r\)[/tex] is given by:

[tex]\[ (x - h)^2 + (y - k)^2 = r^2 \][/tex]

Here, the center of the circle is given as [tex]\((-6, -8)\)[/tex]. Substituting [tex]\(h = -6\)[/tex] and [tex]\(k = -8\)[/tex] into the general equation, we get:

[tex]\[ (x + 6)^2 + (y + 8)^2 = r^2 \][/tex]

Next, we need to determine the radius [tex]\(r\)[/tex]. To do this, we use the point [tex]\((0, -8)\)[/tex], which lies on the circle.

Substitute [tex]\(x = 0\)[/tex] and [tex]\(y = -8\)[/tex] into the equation:

[tex]\[ (0 + 6)^2 + (-8 + 8)^2 = r^2 \][/tex]

This simplifies to:

[tex]\[ 6^2 + 0^2 = r^2 \][/tex]

[tex]\[ 36 + 0 = r^2 \][/tex]

[tex]\[ r^2 = 36 \][/tex]

So, the equation of the circle is:

[tex]\[ (x + 6)^2 + (y + 8)^2 = 36 \][/tex]

Among the given options, we must find the equation that matches this form. The options are:

1. [tex]\((x-6)^2 + (y-8)^2 = 6\)[/tex]
2. [tex]\((x-6)^2 + (y-8)^2 = 36\)[/tex]
3. [tex]\((x+6)^2 + (y+8)^2 = 6\)[/tex]
4. [tex]\((x+6)^2 + (y+8)^2 = 36\)[/tex]

The correct option is:

[tex]\[ (x + 6)^2 + (y + 8)^2 = 36 \][/tex]

Therefore, the correct answer is the fourth option:

[tex]\[ (x+6)^2 + (y+8)^2 = 36 \][/tex]