simplify radicals: 5 sqrt(4) - 3 sqrt(16) = ...?

[tam10]

I do not understand how to get the answer to simplify 5?4 - 3?16
would it be something like

5?2*?2--3?8*2

= 5 * 2 ?2 - 3*2?4 * ?2

= 5 * 2 ?2 - 3*2*2?2 * ?2

= 10?2 - 12?2

= -2?2

I did not think we could end up with a negative number. I am not understanding how to simplify larger numbers.

 

[Mrspi]

Re: simplify radicals

I do not understand how to get the answer to simplify 5?4 - 3?16
would it be something like 5?2*?2--3?8*2 =
5 * 2 ?2 - 3*2?4 * ?2 =
5 * 2 ?2 - 3*2*2?2 * ?2 =
10?2 - 12?2 =
-2?2

I did not think we could end up with a negative number. I am not understanding how to simplify larger numbers.

Start by simplifying each of the radical expressions as much as you can.

let's look at 5 sqrt(4)

What is sqrt(4)? Since 2*2 = 4, sqrt(4) = 2. So, 5 sqrt(4) is the same thing as 5*2, or 10.

Then, look at 3 sqrt(16). Since 4*4 = 16, sqrt(16) = 4. And 3 sqrt(16) is the same thing as 3*4, or 12.

Now....

5 sqrt(4) - 3 sqrt(16) becomes
10 - 12
or, -2