Question

$(7 + \sqrt{7}) \times(7 - \sqrt{7)}$
​

Answer 1

42 is your correct answer of your question

Answer 2

Answer:

$\boxed{42}$

Step-by-step explanation:

$→(7 + \sqrt{7} ) \times (7 - \sqrt{7} ) \\ →7(7 - \sqrt{7} ) + \sqrt{7} (7 - \sqrt{7} ) \\→ 49 - \sqrt[7]{7} + \sqrt[7]{7} - 7 \\ →42$

In the fourth step, -7√7 and +7√7 will be cancelled, because they both have opposite signs.

Other method :

• As there is mentioned to simplify it, that is why I've used the simplification method.
• You can also use the identity : a² - b² = (a+b) (a-b).

____________________________