Question

find the value of (5+√7)(5-√7)​

Answer 1

(5+√7) (5-√7)

→ 5(5-√7) +√7(5-√7)

→25-5√7+5√7-7

→25-7

→ 18

Answer 2

find the value of (5+√7)(5-√7)

let,

5=a

√7=b

According to question

(a+b)(a-b)

$a^2-b^2$

$5^2-\sqrt7^2$

25-7

18 answer