Question

The number (3 -root 7) (3+root 7) is a rational number or irrational number.

Answer 1

Answer:

Rational

Step-by-step explanation:

Use this expression to find the ans on how it is rational:-

(a+b)(a-b) = a^2 + b^2

Answer 2

Answer:

(3-√7)(3+√7)

use the identity (a+b)(a-b) = a^2 - b^2

here a = 3 and b = √7

therefore (3-√7)(3+√7) = 3^2 - (√7)^2

=> 9 - 7 [ √7×√7 = 7 ]

=> 2 it is a rational number