RecycledCDs, Incorporated, offers a choice of 5 used CDs for $23, With each additional CD costing $7. Write a cost function for purchasing 5 or more CDs. What will the cost of buying 12 CDs be? Let x represent the number of CDs over 5.

-- Cost Function

Cost of buying 12CDs is $72

Step-by-step explanation:

Given

Solving (a): Cost Function

Let n represent CDs greater than 5

Substitute:

  and    

Open Bracket

Collect Like Terms

Solving (b): When n = 12

Substitute 12 for n in

Cost of buying 12 CDs is $72

the answer is (-8,-5)

step-by-step explanation:

the endpoint to midpoint is half the length. the length is (-2,-1) so when you are at the midpoint just add it to it to find your answer -6+(-2)= -8 and -4+(-1)=-5 so (-8,-5)