Question

I need some assistance checking my work. My teacher messed up the key. :/
Write the equation of the circle with center and radius:

Answer 1

\[c(1,-3), r=\sqrt{5}\]

Answer 2

I got \[x^2-4x+y^2+8y+20=7\]
Not sure if that is entirely right.

Answer 3

(x-Cx)^2 + (y-Cy)^2 = r^2

Answer 4

ER bah, I goofed

Answer 5

\[C(2,-4), r \sqrt{7}\]

Answer 6

x-1)^2 = x^2 -2x +1

y--3)^2 = y^2 +6y +9

r^2 = 5

Answer 7

Sorry about that.

Answer 8

same procedure, just new numbers :)

Answer 9

x^2-4x+4 +y^2+8x+16 = 7

maybe?

Answer 10

looks fine to me