Question

if a=2+√5/2-√5 and b=2-√5/2+√5 then find the value of a2-b2​

Answer 1

**note:i assume 'a' as 'x'**

x = 2-√5/2+√5  

on rationalization

 

x = (4 + 5 – 4 √5) / – 1

 

x =   4 √5 – 9

 

Now similarly y =   – 4 √5 – 9

 

Now question is asked for x^2 – y^2

= (x+y) * (x – y)

 

=  – 18 * 8 √5

= – 144√5