# Ncert Solutions For Class 9 Maths Ex 2.1

## Ncert Solutions For Class 9 Maths Chapter 2 Ex 2.1

Q.1.Which of the following expressions are polynomials in one variable and which are not? State reasons for your answer:

(i)4x23x+7$4x^{2}-3x+7$

Answer: It is a polynomial in one variable.

(ii) y2+2$y^{2}+\sqrt{2}$

Answer: It is a polynomial in one variable.

(iii) 3t+t2$3\sqrt{t}+t\sqrt{2}$

Answer: It is not a polynomial since the power of the variable is not a whole number.

(iv) y+2y$y+\frac{2}{y}$

Answer: It is not a polynomial since the power of the variable is not a whole number.

(v) x10+y3+t50$x^{10}+y^{3}+t^{50}$

Answer: It is a polynomial in three variables.

Q.2. Write the coefficients of a2 in each of the following:

(i) 2+a2+a$2 + a^{2} + a$

Answer: Coefficient of a2$a^{2}$ is 1.

(ii) 2a2+a3$2 – a^{2} + a^{3}$

Answer: Coefficient of a2$a^{2}$ is -1.

(iii) π2x2+x$\frac{\pi }{2}x^{2}+x$

Answer: Coefficient of a2$a^{2}$ is π2$\frac{\pi }{2}$.

(iv)
2x1$\sqrt{2}x-1$

Answer: Coefficient of a2$a^{2}$ is 0.

Q.3. Give one example each of a binomial of degree 35, and of a monomial of degree 100.

Answer: 3x35+5and4x100$3x^{35}+5\; and\; 4x^{100}$

Q.4. Write the degree of each of the following polynomials:

(i) 5a3+4a2+7a$5a^{3} + 4a^{2} + 7a$

(ii) 3b2$3-b^{2}$

(iii) 5t8$5t – \sqrt{8}$

(iv)8

Q.5. Classify the following as linear, quadratic and cubic polynomial.

(i) a2+a$a^{2} + a$

(ii)aa3$a-a^{3}$

(iii) y+y2+4$y + y^{2} +4$

(iv)1 + x

(v) 3a

(vi) a2$a^{2}$

(vii) 6a3$6a^{3}$