Ask Question
12 December, 23:31

Identify the vertex focus and directrix of the graph x^2-8x-28y-124=0

a. vertex (4,5) focus (4,2) directrix y=2.

b. vertex (-4,5) focus (0,7) directrix y=7

c. vertex (4,-5) focus (4,2) directrix y=-12

d. vertex (-4,5) focus (4,-12) directrix y=2

+3
Answers (1)
  1. 12 December, 23:54
    0
    x^2 - 8x - 28y - 124 = 0

    Rearranging,

    x^2 - 8x = 28y + 124

    Using completing the square method on the left hand side:

    x^2 - 8x + 16 = 28y + 140

    Factoring the left hand and right hand side:

    (x - 4) ^2 = 28 (y + 5).

    Now just factor out 4 and you have

    (x - 4) ² = 4[7 (y + 5) ]

    So, Vertex is at (4, - 5)

    Focus is at F (4, - 5 + 7) = F (4. 2)

    And the directrix is y = - 5 - 7

    = - 12.
Know the Answer?
Not Sure About the Answer?
Find an answer to your question 👍 “Identify the vertex focus and directrix of the graph x^2-8x-28y-124=0 a. vertex (4,5) focus (4,2) directrix y=2. b. vertex (-4,5) focus ...” in 📗 Mathematics if the answers seem to be not correct or there’s no answer. Try a smart search to find answers to similar questions.
Search for Other Answers