Answer:
See below
Step-by-step explanation:
Let's suppose you're getting a new phone plan. The phone plan charges a flat fee of $5 and costs $9 a month. How can we represent this relationship?
Since $5 is a flat fee, it doesn't change based on how many months you've had the plan because it always remains $5, so this is our y-intercept.
Because the plan costs $9 a month, this represents our rate of change, or slope, showing that every month you have the plan, you multiply by $9.
So, we can show this as y=9x+5 where x is the number of months of the phone plan and y is the cost of the phone plan given x amount of months
Now, what if you wanted to know how much the phone plan would cost after 4 months?
Simple enough, we can just substitute x=4 into our equation and get y=9(4)+5=36+5=41. So, getting the phone plan for 4 months costs $41.
Let's take this the other way around. What if we wanted to figure out how many months of the phone plan are covered by $50?
We would then substitute y=50 into our equation and solve for x:
y=9x+5
50=9x+5
45=9x
5=x
This would mean $50 would cover 5 months of the phone plan.
All in all, these are real-life examples of algebra.
