Question

What is the equation of a circle with center (6,-4) and radius 6?

Answer 1

Answer:

$(x-6)^{2} + (y+4)^{2}=36$

Step-by-step explanation:

$(x-h)^{2} + (y-k)^{2}=r^{2}$

h=6

k=-4

r=6

$(x-6)^{2} + (y+4)^{2}=6^{2}$

$x^{2} -12x+36 + y^{2} +8y+16=36\\\\x^{2} +y^{2} -12x +8y +52-36 = 0\\\\x^{2} +y^{2} -12x +8y+ 16 = 0$

Answer 2

Answer:

(x - 6)² + (y + 4)² = 36

Step-by-step explanation:

The equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k) are the coordinates of the centre and r is the radius

here (h, k) = (6, - 4) and r = 6, hence

(x - 6)² + (y - (- 4))² = 6², that is

(x - 6)² + (y + 4)² = 36 ← equation of circle