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

Question

anonymous · Answer

Yes

anonymous · Answer

$$10\sqrt{5}$$

mathteacher1729 · Answer

$$8\sqrt{20} - 6\sqrt{5}$$

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 
$$16\sqrt{5}-6\sqrt{5} =10\sqrt{5}$$

 :)

mathteacher1729 · Answer

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

anonymous · Answer

No your ok, thank you for your help