Question

Select the correct answer. What is the general form of the equation of a circle with its center at (-2, 1) and passing through (-4, 1)? A. x2 + y2 − 4x + 2y + 1 = 0 B. x2 + y2 + 4x − 2y + 1 = 0 C. x2 + y2 + 4x − 2y + 9 = 0 D. x2 − y2 + 2x + y + 1 = 0 Reset Next

Answer 1

Answer B)

Explanation:

( x + 2 )² + ( y - 1 )² = r²

( - 4 + 2 )² + ( 1 - 1 )² = r²

4 = r², than we will plug in to a formula:

( x + 2 )² + ( y - 1 )² = 4

x² + 4 x + 4 + y² - 2 y +1 = 4

x² + y² + 4 x - 2 y + 1 = 0