Complete the square and write the equation in standard form

Complete the square and write the equation in standard form. Then find the center and radios of the circle and graph the equation. x^2 + y^2 +8x - 8y - 17 = 0. The equation of the circle in standard form is

Solution

x²+y²+8x-8y-17=0

x²+8x +16 +y²-8y +16=17+16+16

(x+4)²+(y-4)²=49=7²

comparing it with (x-h)²+(y-k)²=r²

Here center (h,k) = (-4,4)

and radius=7