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Question
In the following, find the value of k for which the given value is a solution of the given equation:
x2 + 3ax + k = 0, x = -a
Solution
We are given here that,
x2 + 3ax + k = 0, x = -a
Now, as we know that x = -a is a solution of the quadratic equation, hence it should satisfy the equation. Therefore substituting x = -a in the above equation gives us,
x2 + 3ax + k = 0
(-a)2 + 3a(-a) + k =0
a2 - 3a2 + k = 0
-2a2 + k = 0
k = 2a2
Hence the value of k = 2a2.
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