What is the general form of the equation of a circle with center at (a, b) and radius of length m?

a: x2 + y2 − 2ax − 2by + (a2 + b2 − m2) = 0

b: x2 + y2 + 2ax + 2by + (a2 + b2 − m2) = 0

c: x2 + y2 − 2ax − 2by + (a + b − m2) = 0

d: x2 + y2 + 2ax + 2by + a2 + b2 = -m2

The equation of a circle with center (h,k) and radius r is


convert it to that form by comleting the square for the x and y terms
or, we can just expand what we know

expand and make it equal to 0
so expanding we get

minus m^2 from both sides

arranging in decreasing power order with m² at the end

that is option A

answer is A

The first one minimumi hope my answer you.