Question

what is the following sum?
$4\sqrt{5} + 2\sqrt{5}$
\bigcirc $6\sqrt{10}$
\bigcirc $8\sqrt{10}$
\bigcirc $6\sqrt{5}$
\bigcirc $8\sqrt{5}$

Explanation:

Step1: Identify like radicals

Both terms have $\sqrt{5}$, so they are like radicals.

Step2: Add the coefficients

The coefficients are 4 and 2. Add them: $4 + 2 = 6$.

Step3: Combine with the radical

Keep the radical $\sqrt{5}$ and multiply by the sum of coefficients: $6\sqrt{5}$.

Answer:

$6\sqrt{5}$ (corresponding to the option with $6\sqrt{5}$)