SOLUTION: The equation {{{ y^2 + 4x + 4y + k = 0 }}} represents a parabola whose latus rectum is: A- 1 B- 2 C- 3 D- 4

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: The equation {{{ y^2 + 4x + 4y + k = 0 }}} represents a parabola whose latus rectum is: A- 1 B- 2 C- 3 D- 4      Log On


   

Question 1184284: The equation +y%5E2+%2B+4x+%2B+4y+%2B+k+=+0+ represents a parabola whose latus rectum is:
A- 1
B- 2
C- 3
D- 4
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

The equation y%5E2%2B4x%2B+4y+%2Bk=0+represents a parabola whose latus rectum is:

y%5E2%2B4x%2B+4y+%2Bk=0
%28y%5E2%2B+4y%29+%2B4x%2Bk=0
%28y%5E2%2B+4y%2Bb%5E2%29-b%5E2+%2B4x%2Bk=0 ...........b=2
%28y%5E2%2B+4y%2B2%5E2%29-2%5E2+%2B4x%2Bk=0
%28y%2B2%29%5E2-4+%2B4x%2Bk=0
%28y%2B2%29%5E2=-4x%2B4-k
%28y%2B2%29%5E2=-4%28x-1%2Bk%2F4%29

Latus rectum =4 units

answer: D: 4