Question

Pls ans this with method . (3 +√5)(3 -√5)​

Answer 1

Answer :-

• ( 3 + √5 ) ( 3 - √5 ) => 4

To Find :-

• The value of ( 3 + √5 ) ( 3 - √5 )

Step By Step Explanation :-

We need to find the value of ( 3 + √5 ) ( 3 - √5 ) .

So let's do it !!

As we know ⤵

$\boxed{ \tt{ \green{(x + y)(x - y) = {x}^{2} - {y}^{2}}}}$

By using the above identity ⤵

$\tt( 3 + \sqrt{5}) ( 3 - \: \sqrt{5} ) \\ \\ \implies \sf{(3)}^{2} - {(\sqrt{5})}^{2} \\ \\ \implies \sf 9 - 5 \\ \\ \implies \sf4$

Therefore, ( 3 + √5 ) ( 3 - √5 ) => 4

Some Identities :-

• ( a + b )² = a² + b² + 2ab

• ( a - b )² = a² + b² - 2ab

• a² - b² = ( a + b ) ( a - b )

• ( a + b + c ) = a² + b² + c² + 2( ab + bc + ac )

__________________________