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Find the value of k, if (x - 1) is a factor of 4x3 + 3x2 – 4x + k.
- A-2
- B-3
- C3
- D2
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Discussion 1
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CCommunity
The given polynomial is: 4x3 + 3x2 – 4x + k.
As we know, for (x – 1) to be a factor of polynomial, putting x = 1 should make the value 0.
∴ 4x3 + 3x2 – 4x + k = 4(1)3 + 3(1)2 – 4(1) + k = 4 + 3 – 4 + k
⇒ 4 + 3 – 4 + k = 0
⇒ k = –3
As we know, for (x – 1) to be a factor of polynomial, putting x = 1 should make the value 0.
∴ 4x3 + 3x2 – 4x + k = 4(1)3 + 3(1)2 – 4(1) + k = 4 + 3 – 4 + k
⇒ 4 + 3 – 4 + k = 0
⇒ k = –3