Question

Find the difference between the cost of 2 line ad and the cost of a 3 line ad.

Answer 1

The piecewise function is given to be:

$a(x)=\begin{cases}45,\text{ when }x\le3 \\ 45+9(x-3),\text{when }x>3\end{cases}$

QUESTION A

For a 2 line ad, the first equation will be used. Therefore:

$a(2)=45$

For a 3 line ad, the first equation will be used. Therefore:

$a(3)=45$

Therefore, the difference is:

$a(3)-a(2)=45-45=0$

The difference is 0.

QUESTION B

For a 10 line ad, we will use the second equation:

$a(x)=45+9(x-3)$

At x = 10,

$\begin{gathered} a(10)=45+9(10-3)=45+9(7) \\ a(10)=45+63=108 \end{gathered}$

The cost of a 10 line ad is 108.

QUESTION C

For an 11 line ad, we will use the second equation.

At x = 11,

$\begin{gathered} a(11)=45+9(11-3) \\ a(11)=117 \end{gathered}$

The cost of an 11 line ad is 117.