NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 2: Polynomials - Exercise 2.1
Question 10

Question.  10

If one of the zeroes of a quadratic polynomial of the form \(x^2+ax+b\) is the negative of the other, then it

(A)

has no linear term and the constant term is negative

(B)

has no linear term and the constant term is positive

(C)

can have a linear term but the constant term is negative

(D)

can have a linear term but the constant term is positive

Detailed Answer with Explanation:

Step 1: Assume the zeroes.

Let the two zeroes be \(r\) and \(-r\).

Step 2: Form the quadratic polynomial.

If \(r\) and \(-r\) are the zeroes, then the polynomial is

\((x - r)(x + r) = x^2 - r^2\).

Step 3: Compare with the given form.

The polynomial becomes \(x^2 + ax + b\).

Here, the coefficient of \(x\) is \(a = 0\), so there is no linear term.

The constant term is \(b = -r^2\).

Step 4: Sign of the constant term.

Since \(r^2 \geq 0\) for all real \(r\),

\(b = -r^2 \leq 0\).

Therefore, the constant term is negative (unless \(r = 0\), in which case the polynomial is just \(x^2\)).

Conclusion: The polynomial has no linear term and the constant term is negative. So the correct option is (A).

NCERT Exemplar Solutions Class 10 – Mathematics – CHAPTER 2: Polynomials – Exercise 2.1 | Detailed Answers