college algebraPlease help Reiny please
posted by ladybug on .
You helped me with this question and this is what I got but my Professor says that each x and y intercept needs to have a coordinate. Where did I go wrong?? Can you help me?
x^2+y^2+4x+2y20=0
x^2+4x+4+y^22y+1=20+4+1
(x+2)^2+(y+1)^2=25this is where you helped me. Then I came and did the x and y intercepts. This what I got. But not a coordinate???
xintercepts are found by setting y=0
(x+2)^2+(01)^2=5^2
x^2+4x+4+1=25
x^2+4x20=0
x=[4+/sqrt((4^2)(4)(1)(20))]/2
=[4+/sqrt(96)]/2
[2+/2sqrt(6)]
yintercepts are found by setting x=0
(0+2)^2 +(y1)^2=5^2
y^22y+1+4=25
y^22y20=0
y=[2+/sqrt((2^2)(4)(1)(20))]/2
=[1+/sqrt(21)]

What you did is correct, but it would have been easier to do it this way:
let y = 0
(x+2)^2 + 1 = 25
(x+2)^2 = 24
x + 2 = ± √24 = ± 2√6
x = 2 ± 2√6
same way for the yintercept
so the xintercepts are:
(2+2√6 , 0) and (2  2√6, 0)
the yintercepts are:
(0, 1+√21) and (0,1  √21)
Your prof seem "picky"
By stating it as the yintercept, you are implying that x = 0
etc