Answer:
A
Step-by-step explanation:
You're looking for x-intercepts
From the graph you know that the x-intercepts are as follows:
x = -4, x = -2, x = 4
And this is when y or f(x) = 0
so you can rewrite each x-intercept as an equation
0 = x + 4
0 = x + 2
0 = x - 4
Now you know each of the terms
f(x) = (x-4)(x+2)(x+4)
Following the table and knowing that the total number of students interviewed were 158 ( we can see this by looking adding either the total number of upperclassment or adding the total number of people with jobs or no jobs, this value is at the bottom right of the table in the figure attached).
Recall that:

In the figure provided each of these terms is highlighted in a different color. To convert these values to their matching probabilities we have to divide each by the total number of students, this is due to the fact that the probability is the number of favorable cases (in this case a group matching the qualities we seek) divided by the total amount of cases ( that is the total number of people interviewed). In the figure the answer is provided. For the intersection of the two events we're looking for people that is both an undercalssman and also has a job.
Answer:
45
Step-by-step explanation:
20 / 9 = 2.222222222223
100 / 45 = 2.222222222223
9 is 45% of 20 and 45 is 45% of 100.
Triangular sequence = n(n + 1)/2
If 630 is a triangular number, then:
n(n + 1)/2 = 630
Then n should be a positive whole number if 630 is a triangular number.
n(n + 1)/2 = 630
n(n + 1) = 2*630
n(n + 1) = 1260
n² + n = 1260
n² + n - 1260 = 0
By trial an error note that 1260 = 35 * 36
n² + n - 1260 = 0
Replace n with 36n - 35n
n² + 36n - 35n - 1260 = 0
n(n + 36) - 35(n + 36) = 0
(n + 36)(n - 35) = 0
n + 36 = 0 or n - 35 = 0
n = 0 - 36, or n = 0 + 35
n = -36, or 35
n can not be negative.
n = 35 is valid.
Since n is a positive whole number, that means 630 is a triangular number.
So the answer is True.