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Question
Find the value of k for which the roots of the quadratic equation 5x2 – 10x + k = 0 are real and equal.
Solution
5x2 – 10x + k = 0
For real and equal roots b2 – 4ac = 0
Where a = 5, b = – 10 and c = k
(– 10)2 – 4(5)(k) = 0
k = `100/20` = 5
∴ k = 5
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