Question

add. write your answer in simplest form.
$-3sqrt{8} + 9sqrt{2}$

Explanation:

Step1: Simplify $\sqrt{8}$

We know that $8 = 4\times2$, and $\sqrt{ab}=\sqrt{a}\times\sqrt{b}$ (where $a\geq0,b\geq0$). So $\sqrt{8}=\sqrt{4\times2}=\sqrt{4}\times\sqrt{2}=2\sqrt{2}$. Then $- 3\sqrt{8}=-3\times2\sqrt{2}=-6\sqrt{2}$.

Step2: Combine like terms

Now we have $-6\sqrt{2}+9\sqrt{2}$. Since the terms have the same radical part ($\sqrt{2}$), we can combine the coefficients: $(-6 + 9)\sqrt{2}=3\sqrt{2}$.

Answer:

$3\sqrt{2}$