Question

3) Situation:It cost $40 a month for a phone plan and $15 for each line.a) What is the Dependent Variable:b) What is the Independent Variable:c) What is the Function rule:d) If the Levine family needs 4 lines, what would be the total cost?

Answer 1

Let:

x = Independent variable = Number of lines

y = Dependent variable = Total cost

b = Cost of the phone plan

a = Cost of each line

a)

The dependent variable is the total cost ( y )

b)

The independent variable is the number of lines ( x )

c)

The function rule is given by:

`\begin{gathered} y=ax+b \\ y=15x+40 \end{gathered}`

d)

x = 4

`\begin{gathered} y(4)=15(4)+40 \\ y(4)=100 \end{gathered}`

The total cost would be $100