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Question
Write the value of λ for which x2 + 4x + λ is a perfect square.
Solution
The given quadric equation is x2 + 4x + λ = 0
Then find the value of k.
Here, a =1, b= 4 and, c = λ
As we know that D = b2 - 4ac
Putting the value of a =1, b = 4 and, c = λ
` = (4)^2 - 4 xx 1 xx λ`
= 16 -4λ
The given equation are perfect square, ifD = 0
14 - 4λ = 0
4λ = 16
`λ = 16/4`
= 4
Therefore, the value of λ = 4.
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