That's a question about graphs.
In the Cartesian coordinate system, we have two axes: The x-axis (horizontal) and the y-axis (vertical).
When we want to represent a equation in the cartesian coodinate system, we associate a point in the x-axis and other in the y-axis. The Cartesian coordinate is represented by (x, y).
To represent some equation in a graph, we need at least two points to draw a line that cross these 2 points.
For example: To represent the equation 
, let's replace the value of <em>x</em>:
- When<em> x = 0</em> →
. Therefore, the coordenate is (0, 1).
- When <em>x = 1</em> →
. Therefore, the coordenate is (1, 2).
Finally, if we draw a line tha cross these 2 points, we will have the graph that represents .
Now you know about it, let's solve our problem?
In that question, we should to find the graph that represents the equation 
, but we don't know the value of <em>k</em>, so what should we do? It's easy:
<em>k </em>is a constant. That means that the value of k never changes. Now, let's analyze a specific case:
If <em>x = 0</em>, so <em>y = 0</em> as well. But why? We know that any number multiplied by 0 is equal 0. Therefore:
- When If <em>x = 0 → </em>
. So, this graph cross the coordinate (0,0).
With the informations that the problem give to us, these are the unique things that we can find, but that's enough.
When we look at the options, just the second graph have a line that cross the coordenate (0, 0). Therefore, the correct answer is the graph below:
I hope I've helped. :D
Enjoy your studies! \o/
