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Question
If 3x2 – kx – 15 = (3x – 5)(x + 3), the value of k is ______.
Options
4
– 4
3
– 3
Solution
If 3x2 – kx – 15 = (3x – 5)(x + 3), the value of k is – 4.
Explanation:
Given
3x2 – kx – 15 = (3x – 5)(x + 3)
= 3x(x + 3) – 5(x + 3)
= 3x2 + 9x – 5x – 15
= 3x2 + 4x – 15
On comparing the coefficient of x on both sides;
`\implies` – k = 4
`\implies` k = – 4
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