Question

Find the equation of the circle with the given center and radius:center (-8,-1) and r = 9

Answer 1

`\begin{gathered} \text{The equation:} \\ (x+8)^2+(y+1)^2=81 \end{gathered}`

Step-by-step explanation:

GIven:

center (-8, -1)

r = radius = 9

Using the formula for equation of circle:

`(x-h)^2+(y-k)^2=r^2`
`\begin{gathered} \text{center (h, k) = (-8, -1)} \\ h\text{ = -8, k=-1} \\ \\ \text{Inserting into the formula:} \\ \mleft(x-\mleft(-8\mright)\mright)^2+\mleft(y-\mleft(-1\mright)\mright)^2=9^2 \end{gathered}`
`\begin{gathered} \text{Multiplication of same sign gives positive sign} \\ (x+8)^2+(y+1)^2=9^2 \\ \\ \text{The equation:} \\ (x+8)^2+(y+1)^2=81 \end{gathered}`