Question

Which of the following is not an irrational number? ​

Answer 1

Answer:

3rd one is not an irrational number.....

Answer 2

Answer:

c) (2+√5)(2-√5) is not an irrational number

Step-by-step explanation:

• (2+√5)(2-√5)
• using the identity (a-b)(a+b)=a²-b², we get,
• =2²-(√5)²
• =4-5
• = -1
• and -1 is a rational number
• so option c is correct (Ans.)

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