Answer:
Step-by-step explanation:
x² + y² + 42x + 38y - 47 = 0
Put the equation into standard (center-radius) form:
regroup terms
(x²+42x) + (y²+38y) = 47
complete the squares:
(x²+42x+21²) + (y²+38y+19²) = 47 + 21² + 19²
(x+21)² + (y+19)² = 849
center at (-21,-19)
radius = √849 units
The general form of the equation for a circle with radius √849 units is:
(x-h)² + (y-k)² = 849
where the (h,k) is the center.