NCERT Solutions
Class 9 - Mathematics - Chapter 2: POLYNOMIALS
EXERCISE 2.1

Question. 1

Which of the following expressions are polynomials in one variable and which are not? State reasons for your answer:

(i) \(4x^2 - 3x + 7\)
(ii) \(y^2 + \sqrt{2}\)
(iii) \(3\sqrt{t} + t\sqrt{2}\)
(iv) \(y + \dfrac{2}{y}\)
(v) \(x^{10} + y^3 + t^{50}\)

Answer:

(i) and (ii) are polynomials in one variable.

(v) is a polynomial in three variables.

(iii) and (iv) are not polynomials because their variable exponents are not whole numbers.

Question. 2

Write the coefficients of \(x^2\) in each of the following:

(i) \(2 + x^2 + x\)
(ii) \(2 - x^2 + x^3\)
(iii) \(\dfrac{\pi}{2} x^2 + x\)
(iv) \(\sqrt{2}x - 1\)

Answer:

(i) 1

(ii) -1

(iii) \(\dfrac{\pi}{2}\)

(iv) 0

Question. 3

Give one example each of a binomial of degree 35, and of a monomial of degree 100.

Answer:

Example binomial of degree 35: \(3x^{35} - 4\)

Example monomial of degree 100: \(\sqrt{2} \, y^{100}\)

Question. 4

Write the degree of each of the following polynomials:

(i) \(5x^3 + 4x^2 + 7x\)
(ii) \(4 - y^2\)
(iii) \(5t - \sqrt{7}\)
(iv) \(3\)

Answer:

(i) 3

(ii) 2

(iii) 1

(iv) 0

Question. 5

Classify the following as linear, quadratic, and cubic polynomials:

(i) \(x^2 + x\)
(ii) \(x - x^3\)
(iii) \(y + y^2 + 4\)
(iv) \(1 + x\)
(v) \(3t\)
(vi) \(r^2\)
(vii) \(7x^3\)

Answer:

(i) quadratic

(ii) cubic

(iii) quadratic

(iv) linear

(v) linear

(vi) quadratic

(vii) cubic

NCERT Solutions Class 9 – Mathematics – Chapter 2: POLYNOMIALS – EXERCISE 2.1 | Detailed Answers