5 Vatsal Asked: December 11, 20192019-12-11T15:16:42+00:00 2019-12-11T15:16:42+00:00In: Class 11 Mathematics 5 For what value of k (4-k)x^2+(2k+4)x+(8k+1)=0 is a perfect square? question Share Facebook 1 Answer Voted Oldest Recent Best Answer Amit Sharma 2019-12-11T15:33:28+00:00Added an answer on December 11, 2019 at 3:33 pm For a perfect square, put D = b^2 – 4ac = 0 [2k + 4]^2 – 4 [4 – k] [8k + 1] = 0 4k^2 + 16 + 16k – 4 [32k + 4 – 8k^2 – k] = 0 4k^2 + 16 + 16k – 128k – 16 + 32k^2 + 4k = 0 36k^2 – 108 k = 0 k^2 – 3k = 0 k(k – 3) = 0 k = 0 or k = 3 1 Reply Share Share Share on Facebook Share on Twitter Share on LinkedIn Share on WhatsApp Leave an answerLeave an answerCancel reply Featured image Select file Browse Click on image to update the captcha. Save my name, email, and website in this browser for the next time I comment.

For a perfect square, put D = b^2 – 4ac = 0

[2k + 4]^2 – 4 [4 – k] [8k + 1] = 0

4k^2 + 16 + 16k – 4 [32k + 4 – 8k^2 – k] = 0

4k^2 + 16 + 16k – 128k – 16 + 32k^2 + 4k = 0

36k^2 – 108 k = 0

k^2 – 3k = 0

k(k – 3) = 0

k = 0 or k = 3