Question

What is the general form of the equation of a circle with a center at (–5, 0) and a radius of 4?

Answer 1

general form of circle with centre h,k and radius r is
\(\large (x-h)^2+(y-k)^2 = r^2\)

Answer 2

for your question
h= -5
k=0
r =4
just plug in!

Answer 3

(x + 5)^2 + (y - 0)^2 = 4^2

Answer 4

correct!
now simplify

Answer 5

x^2 + 25 + y^2 = 16

Answer 6

then I subtract 25 from both sides and get x^2 + y^2 = -9?

Answer 7

\((x+5)^2 = x^2 +10x+25\)

Answer 8

oh yeah so then (y - 0)^2 is just y^2?

Answer 9

yes

Answer 10

so, your equation is
\(x^2+10x+y^2 = -9 \\ or, ~ x^2+y^2+10x+9=0\)

Answer 11

(x + 5)^2 + y^2 = 4

x^2 + (y + 5)^2 = 4

(x + 5)^2 + y^2 = 16

x^2 + (y + 5)^2 = 16
are my choices.. so which one would it be?

Answer 12

It's either A or C right?

Answer 13

"(x + 5)^2 + (y - 0)^2 = 4^2"
this was your reply , so
\((x+5)^2 +y^2 =16\)

Answer 14

its C because 4^2 =16

Answer 15

okay thank you so much! I understand this now :)

Answer 16

welcome ^_^