Chapter 2 Number System Ex 2.2

RBSE Solutions for Class 9 Maths Chapter 2 Number System Ex 2.2

Question 1.
Classify the following numbers as rational or irrational.
RBSE Solutions for Class 9 Maths Chapter 2 Number System 1

Solution:
(i) 2 – √5 is an irrational number.
(ii) (3 + √23) – √23 = 3 + √23 – √23 = 3
Hence, it is a rational number.
$\frac { 2\sqrt { 11 } }{ 7\sqrt { 11 } } =\frac { 2 }{ 7 }$
Hence, it a rational number.
(iv) $\frac { 1 }{ \sqrt { 3 } }$ is an irrational number.
(v) 2π is an irrational number.

Question 2.
Rationalist the denominator of the following:
RBSE Solutions for Class 9 Maths Chapter 2 Number System 2

Solution:

Question 3.
$\frac { 3+2\sqrt { 2 } }{ 3-\sqrt { 2 } } =a+b\sqrt { 2 }$ , where a and b are rational, then find the values of a and b.
Solution:
$\frac { 3+2\sqrt { 2 } }{ 3-\sqrt { 2 } } =a+b\sqrt { 2 }$
Rationalizing the denominator of L.H.S. by multiplying and dividing by 3 + √2
RBSE Solutions for Class 9 Maths Chapter 2 Number System 3