If by standard from you mean numbers (123) and not words then
1 milllion=1000 thousand or 1000*1000 or 1,000,000
1 billion=1000 million=1000*1000*1000=1,000,000,000
so 7billion=7*1000*1000*1000=7,000,000,000
Cosine is

which applies to a right triangle. I hope that helps you.
Answer:
![\sqrt[]{\frac{x+8}{4}}-3](https://tex.z-dn.net/?f=%5Csqrt%5B%5D%7B%5Cfrac%7Bx%2B8%7D%7B4%7D%7D-3)
Step-by-step explanation:

First rewrite
as y

Now swap y and x

Add 8 on both sides.


Divide by 4.


Extract the square root on both sides.
![\sqrt[]{\frac{x+8}{4}}=\sqrt[]{(y+3)^2}](https://tex.z-dn.net/?f=%5Csqrt%5B%5D%7B%5Cfrac%7Bx%2B8%7D%7B4%7D%7D%3D%5Csqrt%5B%5D%7B%28y%2B3%29%5E2%7D)
![\sqrt[]{\frac{x+8}{4}}=y+3](https://tex.z-dn.net/?f=%5Csqrt%5B%5D%7B%5Cfrac%7Bx%2B8%7D%7B4%7D%7D%3Dy%2B3)
Subtract 3 on both sides.
![\sqrt[]{\frac{x+8}{4}}-3=y+3-3](https://tex.z-dn.net/?f=%5Csqrt%5B%5D%7B%5Cfrac%7Bx%2B8%7D%7B4%7D%7D-3%3Dy%2B3-3)
![\sqrt[]{\frac{x+8}{4}}-3=y](https://tex.z-dn.net/?f=%5Csqrt%5B%5D%7B%5Cfrac%7Bx%2B8%7D%7B4%7D%7D-3%3Dy)
Answer:
Let X be the number.
Twice the number would be 2x
The difference between the two, would be subtraction, so you would subtract 4 from 2x
The equation becomes 2x-4 = 16
Now solve for x:
2x-4 = 16
Add 4 to each side:
2x = 20
Divide both sides by 2:
x = 20/2
x = 10
The number is 10.