Answer:
Sorry I could only find the answer to the second part.
y=56x
The answer is X = 5 because first you have to take away 2x from that side so u minus 2x from 4x that gives u: 72 + 2x = 82 then you have to minus 72 from both sides and that gives you 2x = 10 once you have that you divide both sides by 2 because you want the X by itself and once you get that X = 5. Hope this helped!
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.