Question

$\frac{4 - \sqrt{5} }{4 + \sqrt{5} } \times \frac{4 + \sqrt{5} }{4 - \sqrt{5} }$
evaluate​

Answer 1

1 is the answer

$\frac{4 - \sqrt{5} }{4 + \sqrt{5} } \times \frac{4 + \sqrt{5} }{4 - \sqrt{5} } \\ \frac{16 - 5}{16 - 5} \\ \frac{11}{11} \\ 1$

Answer 2

Answer:

by identity a square-b square =(a+b) (a-b)

$\frac{4 - \sqrt{5} }{4 - \sqrt{5} } \times \frac{4 + \sqrt{5} }{4 - \sqrt{5 } } \\ = \frac{16 - 5}{16 - 5 } \\ = 1$