Answer:
a) the common difference is 20
b) 
c) the common difference is -13
d) 
Step-by-step explanation:
a) what is the common difference of the sequence xn
Looking at the table, we get x_3=16, x_4=36 and x_5= 56
Deterring the common difference by subtracting x_4 from x_3 we get
36-16 =20
So, the common difference is 20
b) what is x_8? what is x_12
The formula used is: 
We know common difference d= 20, we need to find 
Using
we can find 

So, We have 
Now finding 

So, 
Now finding 

So, 
c) what is the common difference of the sequence 
Looking at the table, we get a_7=104, a_8=91 and a_9= 78
Deterring the common difference by subtracting a_7 from a_8 we get
91-104 =-13
So, the common difference is -13
d) what is a_12? what is a_15?
The formula used is: 
We know common difference d= -13, we need to find 
Using
we can find 

So, We have 
Now finding
, put n=12

So, 
Now finding
, put n=15

So, 
Answer:
90
Step-by-step explanation:
60/100=x/150
180/300=2x/300
2x=180
x=90
Answer:
(d.) Those who score high on one variable tend to score low on the other.
Step-by-step explanation:
A negative value of correlation coefficient (r) shows a relationship between two variables such that as one variable increases, the other decreases. It shows the inverse relationship between two variables with the dependence determined by the value of the correlation coefficient (r).
It can be observed that for graphs with negative slope, the correlation coefficient (r) is similarly negative. This speaks about its relationship too.
The correlation coefficient being negative doesn't mean the relationship between the two variables in question is bad, it just means that the correlation relationship is inverse (still dependent). A perfectly negative correlation is -1.
Answer:
(1, 4)
Step-by-step explanation:
y=x+3
y=3x+1
y=x+3
x+3=3x+1
x=3x-2
-2x=-2
x=1
y=1+3
y=4