## anonymous 5 years ago Subtract. simplify by collecting like radical term if possible 8sqrt20 -6sqrt5 I got 10sqrt5 is that right????????????

1. anonymous

Yes

2. anonymous

$10\sqrt{5}$

3. mathteacher1729

$8\sqrt{20} - 6\sqrt{5}$ Let's look at the square root of 20 first. 20 = 4*5 and since 4 is a perfect square we can write: $\sqrt{20} = \sqrt{4\cdot 5}=\sqrt{4}\cdot\sqrt{5}=2\sqrt{5}$ So instead of writing $\sqrt{20}$ write $2\sqrt{5}$ and now we have: $8\sqrt{20}=8\cdot (2\sqrt{5})=16\sqrt{5}$. And $16\sqrt{5}-6\sqrt{5} =10\sqrt{5}$ :)

4. mathteacher1729

Argh, I must learn to type faster. :-p

5. anonymous