Question

Expand the brackets and simplify the surds:
(8 + √5) (8 - √5)

Answer 1

(8 + √5)(8 - √5)

there is a formula
(a + b)(a - b) = a² - b²

so
(8 + √5)(8 - √5) = 8² - (√5)²
= 64 - 5
= 59

Answer 2

$\bf{\huge{\boxed{ANSWER}}}$

( 8 + √5 ) ( 8 - √5 )

$\bf{\underline {Applying \: the \: identity}}$

( a + b ) ( a - b ) = a² - b²

=> ( 8 )² - ( √5 )²

=> ( 8 × 8 ) - ( √5 × √5 )

=> 64 - 5

=> $\bf{ 59 \: \: \: \: ANS }$

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