1) This is a combination, so use ⁴⁰C₂.
⁴⁰C₂ = 780
There are 780 handshakes in total.
2) I got my solution by using the combinations formula. Or another way you could do this is to add up... 39 + 38 + 37 + 36 + 35 + 34 + 33 + 32 + 31... +1. You will end up with 780 (I did this to double check my work).
3) The quickest way to figure this out if Drake invited 1,000 people is to use the natural numbers formula = n(n+ 1)/2.
Plug the numbers in: 999(1000)/2 = 499,500
If Drake invited 1,000 people, there would be 499,500 handshakes.
Answer:
See explanation
Step-by-step explanation:
Assuming the given polynomial is

We then rewrite in decreasing powers of u, to get:

The leading term is

The leading coefficient is the coefficient of the leading term.
The leading coefficient is -7.
Rational numbers are basically numbers which are in the form of p/q where p and q are not equal to 0
Therefore p can be both +ve and -ve
But Natural numbers start from 1 , ie they are always positive
Therefore the answer is
B. sometimes