Answer
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The question is an illustration of arithmetic sequence.
<em>The number of conversation for 19 people is 171</em>
<u />
<u>(a) 9 people</u>

9 represents the number of people
8 represents the number of conversation each person had
2 represents the number of people having a conversation at once (i.e 2 people at once)
<u>(b) 19 people</u>
We have:

The number of conversation is:

So, we have:




Hence, the number of conversation for 19 people is 171
Read more about arithmetic sequence at:
brainly.com/question/18109692
Yea his answer is right ^^
Answer:
False
Step-by-step explanation:
Consider the equations with the same number of equations and variables as shown below,
<u>Case 1</u>

This equation has no solution because it is not possible to have two numbers that give a sum of 0 and 1 simultaneously.
<u>Case 2</u>

This equation has infinitely many possible solutions.
Therefore it is FALSE to say a linear system with the same number of equations and variables, must have a unique solution.