Question

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
which answer choice ?

Answer 1

For a circle who's center is (h, k), the general form is \[(x - h)^2 + (y - k)^2 = r^2\]

Answer 2

well the distance from (-2, 1) to (-4, 1) is the radius

the general form is

\[(x- h)^2 + (y - k)^2 = r^2\]

where (h, k) is the centre and r is the radius...

so find the radius and substitute your centre and radius values

Answer 3

thank you but I don't know how to substitute my centre and radius values

Answer 4

so what is your radius value..?

Answer 5

I'm not sure

Answer 6

ok... so this may help