a. Let y = the monthly cost
Let x = the number of GB of data used per month
Equation
Then, the equation that model the cell phone plan is:
[tex]y=10x+45[/tex]
Table
x = -5
[tex]y=10(-5)+45=-50+45=-5[/tex]
x = -3
[tex]y=10(-3)+45=-30+45=15[/tex]
x = 0
[tex]y=10(0)+45=0+45=45[/tex]
x = 1
[tex]y=10(1)+45=10+45=55[/tex]
x = 2
[tex]y=10(2)+45=20+45=65[/tex]
Therefore, the table is:
x y
-5 -5
-3 15
0 45
1 55
2 65
Graph
We graph the equation y = 10x + 45
b. Unlimited data costs $100, this is y = 100, therefore:
[tex]100=10x+45[/tex]
And solve for x
[tex]\begin{gathered} 100-45=10x+45-45 \\ 55=10x \\ \frac{55}{10}=\frac{10x}{10} \\ x=5.5 \end{gathered}[/tex]
Answer: 5.5 GB
