-84
21x4=84 plus the negative
The first one is 2x+y=-1
the second one is 13x+2y-1=0
Answer:
N = 24
Step-by-step explanation:
24 - 4 = 20
The greatest common factor is 8
Missing part of the question
Determine the number of handshakes, i, that will occur for each number of people, n, in a particular room. (people)
Answer:

Step-by-step explanation:
Given
For 5 people

Using the given instance of 5 people, the number of handshakes can be represented as:

The above sequence is an arithmetic sequence and the total number of handshakes is the sum of n terms of the sequence.

Where
--- The first term
--- The last term
So:

