Mathematics>Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
x^2+y^2-18x+16y+120=0
A circle in the xy-plane has the equation shown above. Which of the following gives the coordinates of the center of the circle and the length of its radius?
A.Center: (-9,8)
Radius: 5
B.Center: (9,-8)
Radius: 5
C.Center: (-18,16)
Radius: 2√30
D.Center: (18,-16)
Radius: 2√30