Question

find the value of (4+ √5) (4-√5)

Answer 1

Step-by-step explanation:

(4+√5) (4-√5)

(4)2(√5-√5)

4×4

=16

Answer 2

Answer:

11

Step-by-step explanation:

$(4 + \sqrt{5} )(4 - \sqrt{5} ) \\ = ( {4}^{2} - ( \sqrt{5} )^{2} ) \\ = (16 - 5) = 11$

Use simply the formula for the square of difference

$(x ^{2} - {y}^{2} ) = (x - y)(x + y)$

and you will get the answer.