The sum of the zeroes of the quadratic polynomial \(kx^2+6x+4\) is \(-3\). What is the value of \(k\)?
Answer and explanation
Correct answer: 2
For a quadratic polynomial \(ax^2+bx+c\), the sum of its zeroes is \(-\frac{b}{a}\). Here, \(a=k\) and \(b=6\), so \(-\frac{6}{k}=-3\). Thus, \(6=3k\), giving \(k=2\). Option B results from a sign error; if \(k=-2\), the sum would be \(3\). Exam tip: use the coefficient formula \(-\frac{b}{a}\) directly for the sum of zeroes.
Frequently asked questions
What is the correct answer to this question?
2
Why is this the correct answer?
For a quadratic polynomial \(ax^2+bx+c\), the sum of its zeroes is \(-\frac{b}{a}\). Here, \(a=k\) and \(b=6\), so \(-\frac{6}{k}=-3\). Thus, \(6=3k\), giving \(k=2\). Option B results from a sign error; if \(k=-2\), the sum would be \(3\). Exam tip: use the coefficient formula \(-\frac{b}{a}\) directly for the sum of zeroes.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Polynomials. Topic: Polynomials in one variable.
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