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Question
If the equation x2 + 4x + k = 0 has real and distinct roots, then
Options
k < 4
k > 4
k ≥ 4
k ≤ 4
Solution
The given quadric equation is x2 + 4x + k = 0, and roots are real and distinct.
Then find the value of k.
Here, a = 1, b = 4 and , c = k
As we know that `D = b^2 - 4ac`
Putting the value of a = 1, b = 4 and , c = k
` (4)^2 - 4 xx 1 xx k `
= 16 - 4k
The given equation will have real and distinct roots, if D > 0
16 - 4k > 0
4k < 16
` k< 16/4`
< 4
Therefore, the value of k < 4 .
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