Question

3 A solve the following?
7 A = {2,3,5,7² , B = { 1,3,6,7}
find AB​

Answer 1

3+√7 / 3-√7

multiply 3+√7 on both numerator and denomerator

 (3+√7)² /  (3-√7)(3+√7) = a+b√7

⇒9 + 7 + 6√7 / 3² -√7²   = a+b√7

⇒16+ 6√7 / 9-7              =a+b√7

⇒16+ 6√7 / 2                  =a+b√7

⇒2(8+3√7)/2                  =a+b√7

⇒8 +3√7                          =a+b√7

on compairing both sides

a=8

b=3