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Question
Choose the correct answer from the given four options :
If the equation 3x² – kx + 2k =0 roots, then the the value(s) of k is (are)
Options
6
0 Only
24 only
0
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Solution
3x² – kx + 2k = 0
Here, a = 3, b = -k, c = 2k
b2 – 4ac
= (–k)2 – 4 x 3 x 2k
= k2 – 24k
∴ Roots are equal.
∴ b2 – 4ac = 0
∴ k2 – 24k = 0
⇒ k(k – 24) = 0
Either k = 0
or
k - 24 = 0,
then k = 24
∴ k = 0, 24.
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