Estimate:6000
You can use distributive property
Answer:
2x(2x-1)
Step-by-step explanation:
![4 {x}^{2} - 2x \\ \\ = 2x(2x - 1) \\](https://tex.z-dn.net/?f=4%20%7Bx%7D%5E%7B2%7D%20%20-%202x%20%5C%5C%20%20%5C%5C%20%20%3D%202x%282x%20-%201%29%20%5C%5C%20)
Answer:
They can choose the 2 volunteers in 28 different ways
Step-by-step explanation:
Well, as the research group has to choose 2 volunteers out of 8, this means that it doesn't matter the order in which they choose them as long as they are two.
In statistics this is considered a counting technique and is called combination.
The combination formula is:
![C(n,r)=\frac{n!}{r!(n-r)!}](https://tex.z-dn.net/?f=C%28n%2Cr%29%3D%5Cfrac%7Bn%21%7D%7Br%21%28n-r%29%21%7D)
where
is the set of elements
and
is the number of elements taken from n
Then
and ![r= 2](https://tex.z-dn.net/?f=r%3D%202)
We replace in the combination formula:
![C(8,2)=\frac{8!}{2!(8-2)!}](https://tex.z-dn.net/?f=C%288%2C2%29%3D%5Cfrac%7B8%21%7D%7B2%21%288-2%29%21%7D)
![C(8,2)=\frac{8!}{2!(6!)}](https://tex.z-dn.net/?f=C%288%2C2%29%3D%5Cfrac%7B8%21%7D%7B2%21%286%21%29%7D)
![C(8,2)=\frac{40320}{2(720)}](https://tex.z-dn.net/?f=C%288%2C2%29%3D%5Cfrac%7B40320%7D%7B2%28720%29%7D)
![C(8,2)=\frac{40320}{1440}](https://tex.z-dn.net/?f=C%288%2C2%29%3D%5Cfrac%7B40320%7D%7B1440%7D)
![C(8,2)=28}](https://tex.z-dn.net/?f=C%288%2C2%29%3D28%7D)
<em><u>This result means that Medical research group can choose the 2 volunteers in 28 different ways</u></em>