Question

Find the value of $(\sqrt{2}+\sqrt{2})(\sqrt{2}-\sqrt{2})$.

• A. True
• B. 1
• C. 2
• D. 3

Answer 1

The correct option is A

True

A common tendency to solve this question is to apply the algebraic identity $(a^2-b^2)=(a+b)(a-b)$. But by observation, we can see that $(\sqrt{2}-\sqrt{2})$, which is one of the factors, will result in 0, thus making the final value of the whole expression as 0 i.e.
$(\sqrt{2}+\sqrt{2})(\sqrt{2}-\sqrt{2})$
$=(\sqrt{2}+\sqrt{2})\times \left(0\right)$
$=0$