Question

simplify (-3-√5)(-3+√5)

Answer 1

$(a + b)(a - b) = {a}^{2} - {b}^{2}$

(-3-√5)(-3+√5 )= (-3)^2 - (√5)^2
=9-5
=4

Answer 2

GIVEN :

(√3 - √5) (√3 + √5)

TO DO :

To solve the given expression.

FORMULA USED :

(a - b)(a + b) = {a}^{2} - {b}^{2}(a−b)(a+b)=a

2

−b

2

SOLUTION :

It is given that, (√3 - √5) (√3 + √5)

we will solve this by using the formula =>

(a - b)(a + b) = {a}^{2} - {b}^{2}(a−b)(a+b)=a

2

−b

2

here, in (√3 - √5) (√3 + √5)

a = √3 and b = √5

⟹(√3 - √5) (√3 + √5) ={( \sqrt{3}) }^{2} - {( \sqrt{5}) }^{2}⟹(√3−√5)(√3+√5)=(

3

)

2

−(

5

)

2

⟹(√3 - √5) (√3 + √5) =3 - 5⟹(√3−√5)(√3+√5)=3−5

⟹(√3 - √5) (√3 + √5) = - 2⟹(√3−√5)(√3+√5)=−2

ANSWER : -2

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✦ More Formulae :-

1. (a+b)² = a²+b²+2ab

2. (a-b)² = a²+b²-2ab