Y=mx+b
m=slope
b=yintercept
given
slope=-1/4
yint=5
y=-1/4x+5
Answer:
THE ANSWER IS OPTION B
Because it has angles and all of them are not the same measure
Answer:
Part A) see the explanation
Part B) 
Step-by-step explanation:
Part A)
we know that
A relationship between two variables, x, and C, represent a proportional variation if it can be expressed in the form
or 
Let
C ---> is the total cost (represent the output or dependent variable)
x ----> is the number of books (represent the input or independent variable)
In this problem
we have a proportional relationship between the variables x and C
Part B) we know that
The linear equation is given by

The constant of proportionality k is the same that the slope or unit rate of the linear equation
In this problem the constant k is given

so

For x=12 books
substitute in the equation and solve for C

In function notation

See attached picture for the answer:
you don't say how to round the answer so I did not round it.
GCF = 20
Reduce the fraction by dividing
the numerator and denominator by 20
and get the simplified answer
<span><span>20 ÷ 20=1 || 80 ÷ 20</span>=4
<em>1/4</em> is your answer! :D</span>