A circle is defined by the equation x2 + y2 + 8x + 22y + 37 = 0. What are the coordinates for the center of the circle and the length of the radius? A. (-4, -10), 11 units B. (-4, -11), 10 units C. (-11, -4), 10 units D. (4, 11), 10 units
standard equation of a circle is (x-h)²+(y-k)²=r², (h, k) is the center of the circle, r is the radius. rearrange the equation: x²+8x+y²+22y=-37 half of 8 is 4, 4²=16 half of 22 is 11, 11²=121
x²+8x+16+y²+22y+121=-37+16+121 (x+4)²+(y+11)²=100 so the center is at (-4, -11) and the radius is 10. B is the answer.
