Been a bit since i’ve done this kind of problem.
X+4=20
X is the number of hours needed to work, while 4 is the hours already there.
Answer:
Step-by-step explanation:
Key to this method is remembering that

So, if you divide the coefficient of x by 2 and square it, that will complete the square. With that in mind, things are easy.
6/2 = 3, so add 

So, c=9
Similarly, for the other two,

You don't really have to worry about the sign, since squaring will always make it positive

Answer:
1 $16.50
2 $28.50
3 $40.50
$4.50 + $12c
$100.50
Step-by-step explanation:
Please find attached the complete question
Total cost in dollars = fixed cost + (variable cost x number of CDs bought)
fixed cost = $4.50
variable cost = $12
number of cds bought = c
total cost in dollars = $4.50 + $12c
total cost in dollars when 1 cd is bought = $4.50 + $12(1) = $16.50
total cost in dollars when 2 cds are bought = $4.50 + $12(2) = $28.50
total cost in dollars when 3 cds are bought = $4.50 + $12(3) = $40.50
total cost in dollars when 8 cds are bought = $4.50 + $12(8) = $100.50
Yes.
They both will end with the equation
.. y = -2x +9