Answer:
k = 1
Explanation:
Given
x² + y² - 2y - 11 = 0 ( add 11 to both sides )
x² + y² - 2y = 11
To express in standard form use the method of completing the square on
y² - 2y
To complete the square
add ( half the coefficient of the y- term )² to both sides
x² + y² + 2(- 1)y + 1 = 11 + 1
x² + (y - 1)² = 12 ← as required
with k = 1