simplify the rational expression.\n$3\\sqrt{5} + \\sqrt{45}$

Explanation:

Step1: Simplify $\sqrt{45}$

We know that $45 = 9\times5$, and $\sqrt{ab}=\sqrt{a}\times\sqrt{b}$ (for $a\geq0,b\geq0$). So $\sqrt{45}=\sqrt{9\times5}=\sqrt{9}\times\sqrt{5}=3\sqrt{5}$.

Step2: Combine like terms

Now we have $3\sqrt{5}+3\sqrt{5}$. Since these are like terms (both have $\sqrt{5}$), we can add the coefficients: $(3 + 3)\sqrt{5}=6\sqrt{5}$.

Answer:

$6\sqrt{5}$