(11*5)+(4*10)=95
11+4=15
Both are equal to the constraints of the word problem and there for justified.
-(-2-5x)+(-2)=18
2+5x-2=18
5x=18
x=18/5=3.6
Let u = x², then we would have u² + 5u - 6 = 0
From here, we can factor it and get us (u-1)(u+6) = 0
So our solution for u is u = -6 or 1.
Now substitute u back to x².
x² = -6 or 1
x = ±√(-6) or ±√1
Since ±√(-6) is not real number, we ignore it.
Which leave us x = ±√1 = <span>±1
So our real solution is x = -1 or 1.</span>
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
y=-1/2x-4
I could be wrong. Not my strong subject.
-Seth