Answer:
Frank must buy 2 pens to have equal number of each pens
Since this is an arithmetic sequence, you can conclude that
the addition to the number is constant.
Let x = the number asked
k = constant
number added to the sequence
7 + k = x
x + k = 17
Solve the system of equation:
7 + k + k = 17
7 + 2k = 17
2k = 10
k = 5
Therefore, the missing number is 12 (7 + 5).
Answer:
See explanation.
Step-by-step explanation:
We need a point and a slope to have a point slope equation.

We need a slope and y-intercept to write in slope intercept form.

A)
or 
B) 
C) 
D) 