Question

Find it is rational or irrational (4+√5)×(4-√5)??

Answer 1

AnsweR:

(4+√5)(4-√5)

We need to solve this to find out whether it is rational or irrational.

➜16 - 4√5 + 4√5 - 5

➜16 - 5

➜11

Hence, it can be concluded that it is rational number.

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What is Rational Number ?

A number which can be written in p/q form where p and q are integers and q is not equal to 0, is called a rational number.

What is Irrational Number ?

A irrational number can not be written in p/q form where p and q are integers and q is not equal to 0, is called an irrational number.

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Answer 2

Answer:

Given number is rational one.

Step-by-step explanation:

Given number :

• (4+√5)(4-√5)

To find :

• Given number is rational or irrational

Solution :

We know that,

$\huge{\boxed{\red{\sf{a^2\:-\:b^2\:=\:(a\:+\:b)(a\:-\:b)}}}}$

Here, (a+b) = (4+√5) and (a-b) = (4-√5)

†Putting the values,

: $\implies$ (4)² - (√5)²

: $\implies$ 16 - 5

: $\implies$ 11

$\therefore$ Given number is rational one.

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Rational number:

The number which can be written in the form of p/q, where p and q are Integers and q ≠ 0 is termed as rational number.