Y = -5x +18
x can be any number, y can be change due to x value
There are 
ways of picking 2 of the 10 available positions for a 0. 8 positions remain.
There are 
ways of picking 3 of the 8 available positions for a 1. 5 positions remain, but we're filling all of them with 2s, and there's 
way of doing that.
So we have
The last expression has a more compact form in terms of the so-called multinomial coefficient,
Mean is when you take all the numbers and add them together and divide by the amount of numbers there
Example: Find the mean of :3,4,6,7
So you a 3+4+6+7=20 divide that by 4(because there you added 4 numbers) and that equals 5
