Write the equation of the circle:
center: (-9, 0), diameter: 10

Answer:
[tex](x+9)^2+y^{2}=25[/tex]
Step-by-step explanation:
The equation of a circle is [tex](x-h)^2+(y-k)^2=r^2[/tex] where [tex](h,k)[/tex] is the center of the circle and [tex]r[/tex] is the radius of the circle.
Given the circle's diameter is [tex]d=10[/tex], then its radius is [tex]r=\frac{10}{2}=5[/tex].
Therefore, the equation of the circle is [tex](x+9)^2+y^{2}=25[/tex]