Rule: with any inscribed quadrilateral, the opposite angles are supplementary (they add to 180 degrees)
Based on that rule, we can say
d+100 = 180
d+100-100 = 180-100
d = 80
Answer: 80
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
Answer:
<h3>A. y=-2x+3z+25</h3>
Step-by-step explanation:
Isolate the term of x and y from one side of the equation.
<u>To solve:</u>

<h3>2x+y-3z=25</h3>
<u>First, you have to subtract by 2x-3z from both sides.</u>

<u>Solve.</u>

- <u>Therefore, the correct answer is "A. y=-2x+3z+25".</u>
I hope this helps, let me know if you have any questions.
Answer:
-7×-9
=63
Step-by-step explanation:
If u multiple - with -, I'll get + sign
Answer: …
Step-by-step explanation: you need an image