Question:
Find the center of the circle whose equation is x² + y² - 4x + 6y + 4 = 0 ?
A(4, -3)
B(2, -3)
C(2, 3)
D(0, 1)
Answer:
B. (2, -3)
Explanation:
If the circle with base (h, k) passes through the point (x, y) then equation of the circle = (x - h)² + (y - k)² = r² x² + y² -2hx - 2yk + h² + k² = r² Center = (coefficient of x/2 , coefficient of y/2) x² + y² - 4x + 6y + 4 = 0 Center = (4/2 , -6/2) = (2, -3)