Mathematics
Find the value of k for which equation 4x2 + 8x - k = 0 has real roots.
Quadratic Equations
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Answer
Since equations has real roots, D ≥ 0
∴ b2 - 4ac ≥ 0
⇒ 82 - 4(4)(-k) ≥ 0
⇒ 64 + 16k ≥ 0
⇒ 16k ≥ -64
Dividing both sides by 16 we get,
⇒ k ≥ -4
Hence, k ≥ -4.
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