Question

simplify (√13+√5)(√13-√5)

Answer 1

to simplify

( √13 + √5 ) ( √13 - √5 )

as we can do like this

( a + b) ( a - b) ^2


( √13 )^2 - (√5)^2.


13 - 5


= 8


hence answer is 8

Answer 2

Concept:

From algebraic identities web have that the difference between squares if two numbers is given by the product of addition and subtraction of that two numbers.

In mathematical words we can say that, $a^2-b^2=(a+b)(a-b)$

Also the square of a square root of a number gives back that number itself.

$(\sqrt{a})^2=a$

Given:

Given that the algebraic expression is (√13+√5)(√13-√5)

Find:

The value of the above algebraic expression.

Solution:

Given algebraic expression is given by,

(√13+√5)(√13-√5)

Applying the abovementioned algebraic identities we get,

$(\sqrt{13}+\sqrt5)(\sqrt{13}-\sqrt5)$

$=(\sqrt{13})^2-(\sqrt5)^2$

Since the values of $(\sqrt{13})^2=13,(\sqrt5)^2=5$, so,

= 13 - 5

= 8

Hence the value of the given algebraic expression (√13+√5)(√13-√5) is given by 8.

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