Question

Which is the irrational number(a) 2-√5 (b) (3 + √ 23) - √23 (c) 2√7/2√7 (d) 1/√2​

Answer 1

ALL ARE IRRATIONAL EXPECT C. BECAUSE THEIR NUMERATOR AND DENOMINATOR CANCEL AND IT COMES RATIONAL

Answer 2

Answer:

(i) 2 - √5 We kno that √5 = 2.236..., which is an irrational number 2 - √5 = 2 - 2.236.. = -0.236..., which is also an irrational number. Therefore, we conclude that 2 - √5 is an irrational number. (ii) (3 +√23) - √23 (3 +√23) - √23 = 3 +√23 - √23 = 3. Therefore, we conclude that (3 +√23) - √23 is a rational number (iii) 2√7/7√7 We can cancel √7 n the numerator and denominator, as √7 is the the common number in numerator as well as denominator, to get 2√7/7√7 = 2/7 Therefore, we conclude that 2√7/7√7 is rational numberRead more on Sarthaks.com - https://www.sarthaks.com/111354/classify-the-following-numbers-as-rational-or-irrational-i-2-5-ii-3-23-23-iii-27-77