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In the following determine the set of values of k for which the given quadratic equation has real roots: 2x2 − 5x − k = 0 - Mathematics

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प्रश्न

In the following determine the set of values of k for which the given quadratic equation has real roots:

2x2 − 5x − k = 0

योग
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उत्तर

The given quadric equation is 2x2 − 5x − k = 0, and roots are real

Then find the value of k.

Here,

a = 2

b = −5

c = k

As we know that D = b2 − 4ac

Putting the value of a = 2, b = −5 and c = k

= (−5)2 − 4 × (2) × (−k)

= 25 + 8k

The given equation will have real roots, if D ≥ 0

25 + 8k ≥ 0

8k ≥ −25

k ≥ `−25/8`

Therefore, the value of k ≥ `−25/8`

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अध्याय 5: Quadratic equations - Exercise 5D [पृष्ठ ७८]

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नूतन Mathematics [English] Class 10 ICSE
अध्याय 5 Quadratic equations
Exercise 5D | Q 7. (iv) | पृष्ठ ७८

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