Question

Find the value of $(\sqrt{5}+\sqrt{5})(\sqrt{5}-\sqrt{5})$.

• A. \N

Answer 1

The correct option is A 0.0
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 $(\sqrt{5}-\sqrt{5})$, which is one of the factors, will result in 0, thus making the final value of the whole expression as 0 i.e.
$(\sqrt{5}+\sqrt{5})(\sqrt{5}-\sqrt{5})$
$=(\sqrt{5}+\sqrt{5})\times \left(0\right)$
$=0$