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Subject - Mathematics:

General

MCQ - 371-9103

Question:

If the sum of the roots of the equation 3x2 – (3k – 2) x – (k – 6) = 0 is equal to the product of its roots then k = ?

  1. 1
  2. – 1
  3. 0
  4. – 1

Correct Answer: D

Explanation:

Let the roots of the given quadratic equation 3x2 – (3k – 2)x – (k – 6)=0 be α and β.
Now,
sum of roots = α + β = (3k – 2)/3 and,
product of roots = αβ = – (k – 6)/3
[∵ If α and β are the roots of quadratic equation ax2 + bx + c=0 then α + β = – b/a and αβ = c/a]
According to question –
sum of roots = product of roots
∴ α + β = αβ
⇒ (3k – 2)/3 = – (k – 6)/3
⇒ 3k – 2 = – k + 6
⇒ 4k = 8
∴ k = 2
Hence, The value of k is 2.

Record Performance

504 MCQ for effective preparation of the test of General of Mathematics section.

Read the MCQ statement: If the sum of the roots of the equation 3x2 – (3k – 2) x – (k – 6) = 0 is equal to the product of its roots then k = ? , keenly and apply the method you have learn through the video lessons for General to give the answer. Record your answer and check its correct answer and video explanation for MCQ No. 371-9103.

How to Answer

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