The 3 represents how many times the species multiplies.
We're going to be using combination since this question is asking how many different combinations of 10 people can be selected from a set of 23.
We would only use permutation if the order of the people in the committee mattered, which it seems it doesn't.
Formula for combination:

Where
represents the number of objects/people in the set and
represents the number of objects/people being chosen from the set
There are 23 people in the set and 10 people being chosen from the set


Usually I would prefer solving such fractions by hand instead of a calculator, but factorials can result in large numbers and there is too much multiplication. Using a calculator, we get

Thus, there are 1,144,066 different 10 person committees that can be selected from a pool of 23 people. Let me know if you need any clarifications, thanks!
~ Padoru
The perimeter is simple the sum of the side lengths so:
4x-1+4x+2+3x+4=49 combine like terms on left side
11x+5=49 subtract 5 from both sides
11x=44 divide both sides by 11
x=4
Let's find x. This will allow us to find the value of the second expression.
x - 3 = 1
x = 4
Now, we can simply plug this x-value into the second expression to obtain 4^2 - 3(4) - 1 = 3.
Thus, our answer is 3.