Question

if x =root 7+root5 and y=root7-root5 find xy​

Answer 1

Answer:

2

Step-by-step explanation:

x = √7 + √5 , y = √7 - √5

xy = (√7 + √5)(√7 - √5)

xy = (√7)² - (√5)²........... (a+b)(a-b) =

a² - b²

xy = 7 - 5.

x = 2.

HOPE IT HELPS YOU ☺️☺️

PLEASE MARK BRAINLIEST.

☺️☺️THANKS ☺️☺️

Answer 2

The value of $xy$ is 2.

Step-by-step explanation:

Given:

$x=\sqrt{7} +\sqrt{5}$.

$y=\sqrt{7} -\sqrt{5}$.

To Find:

The value of $xy$.

Concept Used:

As per the distributive Property  when a factor is multiplied by the sum/addition of two terms, it is required to multiply each of the two numbers by the factor, and finally do the addition operation.

P ( Q+ R) = PQ + PR

Where P, Q and R are three different values.

Solution:

$x=\sqrt{7} +\sqrt{5}$

$y=\sqrt{7} -\sqrt{5}$

$xy=(\sqrt{7} +\sqrt{5} )\times(\sqrt{7} -\sqrt{5} )$

Using the the distributive Property.

      $=\sqrt{7} \times\sqrt{7} -\sqrt{7}\times \sqrt{5} +\sqrt{5} \times\sqrt{7} -\sqrt{5}\times \sqrt{5}$

      $=7 -\sqrt{7}\times \sqrt{5} +\sqrt{5} \times\sqrt{7} -5$

     $=7 -\sqrt{35}+\sqrt{35} -5$

     $=2$

Thus,  the value of $xy$ is 2.

#SPJ2