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Question
In each of the following determine the; value of k for which the given value is a solution of the equation:
x2 + 2ax - k = 0; x = - a.
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Solution
Since, x = -a is a root of the equation
x2 + 2ax - k = 0
⇒ (-a)2 + 2a x (-a) - k = 0
⇒ a2 - 2a2 - k = 0
⇒ -k = a2
⇒ k = -a2.
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