Question
If the roots of equation x2+4x+c=0 are real then c≥4.
Answer: Option B
:
B
Given, x2+4x+c=0
Value of discriminant, Δ=b2−4ac=42–4c=16−4c
The roots of quadratic equation are real thenΔ≥016–4c≥0−4c≥−164c≤16
(The inequality changes when the equation is multiplied by ′−ve′
∴c≤4
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:
B
Given, x2+4x+c=0
Value of discriminant, Δ=b2−4ac=42–4c=16−4c
The roots of quadratic equation are real thenΔ≥016–4c≥0−4c≥−164c≤16
(The inequality changes when the equation is multiplied by ′−ve′
∴c≤4
Was this answer helpful ?
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