To sketch y^2 + 6y +8x +25=0
We
know that this is second degree expression in y. So it is
parabola.
Now put this in he standard form (y-k)^2 = 4a(x-h) , which
is astandard parabola with vertex at (h,k) and focal length a . The focus being located at (h+a
, k).
y^2+6y = -8x-25
We add 3^2 = 9
both sides:
y^2-6y +3^2 =
-8x-25+9
(y-3)^2 = - 8x-16.
(y-3)^2 =
4(-2)(x+2).
Therefore this is a parabola with vertex at (h,k) = (-2
, 3) with focus at (-2-2 , 3) = (-4, 3) and focal length of 2.
The
axis of symmetry is y = 3.
The parabola is open towards
left.
The parabola intercepts x axis at x where (0-3)^2 = -8(x+2) .
Or at x= (9/-8) - 2 = -25/8. The parabola has no y intercepts.intercepts
.
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