what (5 -radical 2)(5+radical 2)

Answer 1

Use the fact that (a + b)(a - b)
= a^2 - b^2,
The answer is 25 - 2 = 23

Answer 2

(5 -√2)(5+√2)
= 25 - 2
= 23

this resembles the difference of square pattern
(a+b)(a-b) = a^2 - b^2