Question

Using the following equation, find the center and radius:

x2 + 2x + y2 + 4y = 20 (5 points)
Select one:
a. The center is located at (1, 2), and the radius is 25.
b. The center is located at (-1, 2), and the radius is 25.
c. The center is located at (-1, -2), and the radius is 5.
d. The center is located at (1, 2), and the radius is 5.

Answer 1

@eliassaab

Answer 2

@robtobey @ganeshie8 @gudden

Answer 3

complete the square for \(x\) terms
complete the square for \(y\) terms

Answer 4

get the equation into form :
\(\large \mathbb{(x-h)^2+(y-k)^2 = r^2}\)

Answer 5

center = \(\large \mathbb{(h,k)}\)
radius = \(\large \mathbb{r}\)

Answer 6

what is that formula called

Answer 7

thats the equation for standard form of \(circle\)

Answer 8

is the radius 5?

Answer 9

if u want answer :
http://www.wolframalpha.com/input/?i=x2+%2B+2x+%2B+y2+%2B+4y+%3D+20+&dataset=

Answer 10

c

Answer 11

but im sure u wanto knw HOW to solve as well ? :)

Answer 12

oh i knew it was C thnx can you help me on some more please

Answer 13

ok, but i feel u still have problems wid 'completing the square' method ?

Answer 14

maybe we will see:)

Answer 15

i mean, did u get, how to complete the square ha ?
or simply rushing after answers lol

Answer 16

yes i did i just need checking and ill tag you for the next question ok

Answer 17

ok thats good :) in the next question show ur work also, so that i wont be asking u so many questions like this ok ?

Answer 18

ok