Let x= number rows
Then x + 5 = number of seats per row
x(x+5) = 126
X^2 + 5x = 126
x^2 + 5x -126 = 0; now factor or use quadratic:
(x+14)(x-9) = 0; so the answers are either -14, or 9, and since -14 is not possible in this case because you can't have a negative number of rows, the answer is 9 rows.
Check work: number of rows = 9, number of seats per row = 9+ 5= 14, and 9 x 14 = 126
Answer:
a) 
b) 
c) 
d) 
e) The intersection between the set A and B is the element c so then we have this:

Step-by-step explanation:
We have the following space provided:
![S= [a,b,c,d,e]](https://tex.z-dn.net/?f=%20S%3D%20%5Ba%2Cb%2Cc%2Cd%2Ce%5D)
With the following probabilities:

And we define the following events:
A= [a,b,c], B=[c,d,e]
For this case we can find the individual probabilities for A and B like this:


Determine:
a. P(A)

b. P(B)

c. P(A’)
From definition of complement we have this:

d. P(AUB)
Using the total law of probability we got:

For this case
, so if we replace we got:

e. P(AnB)
The intersection between the set A and B is the element c so then we have this:

150 divided by 20 is 7 with a remainder of 10
The quotient is 7, but the answer is 8 I'm not sure if this is what you were looking for but I hope it helped