ParabolaMedium
Question
The equation of the directrix of the parabola y2 + 4y + 4x + 2 = 0 is
Options
A.x = - 1
B.x = 1
C.x = -3/ 2
D.x = 3/ 2
Solution
Given, y2 + 4y + 4x + 2 = 0
⇒ (y + 2)2 + 4x - 2 = 0 ⇒
⇒ (y + 2)2 = - 4
Replace y + 2 = Y,
We have, Y2 = - 4X
This is a parabola with directrix at X = 1
⇒
⇒ 
⇒ (y + 2)2 + 4x - 2 = 0 ⇒
⇒ (y + 2)2 = - 4
Replace y + 2 = Y,
We have, Y2 = - 4X
This is a parabola with directrix at X = 1
⇒
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