Question

Kim bought $100 worth of stock and gained $25 per year. Ari bought $400 worth of stock and lost $35 per year. Use x for time and y for stock value. Graph the equations that represent each situation. The first one is done for you.

Answer 1

1. Kim's case:
We know for our problem that she will gain $25 each year, so if $x$ represents the number of years, she will gain $25x$, where $x$ is the number of years. We also know that her initial investment is $100. If we let $y$ represent the stock value after $x$ years, we can relate the quantities with the following equation:
$y=25x+100$

We can conclude that the first image is the graph of the equation that represent Kim's situation.

2. Ari's case:
In this case, he is losing $35 per year. Let $x$ represent the number of years. Since we know that losses are represented with a minus sign, he will lose -35x per year. Now, we know for our problem that her initial investment is $400. If we let $y$ represent the stock value after $x$ years, we can relate the quantities with the following equation:
$y=-35x+400$

We can conclude that the second image is the graph of the equation that represent Ari's situation.