Question

4+√5 4+√5 4-√5 + 4-√5​

Answer 1

Answer:

121

Step-by-step explanation:

(4+sqrt(5)) x (4+sqrt(5)) x (4-sqrt(5)) x (4-sqrt(5))

= {(4+sqrt(5)) x (4-sqrt(5))} x {(4+sqrt(5)) x (4-sqrt(5))}

= (4^2 - sqrt(5)^2) x (4^2 - sqrt(5)^2) using difference of two squares rule

= (16 - 5) x (16 - 5)

= 11 x 11

121