Since Y is greater than -6 the symbol has to point away from the -6 and towards the y. And because Y is less than 0, the symbol has to point towards the zero and away from they. -6<y<0
Okay, let's see...
The problem is asking for a linear equation most likely in the form of y=mx+b
y is another way to say f(x)
<em>m = slope </em>
<em>b = y intercept </em>
Let's start with the y intercept first.
Y intercept means ' When does the line touch (intercept) the y axis.
In this case, if you look at the graph, the line <em>touches </em>the y axis at -1.
-1 will replaces b
To find the slope we are going to take 2 precise points from the graph.
Lets use <em>(0,-1)</em> and <em>(-6,4) </em>
To find the slope, we're going to use 
4 - (-1) / -6 - 0
Solve, our slope is 5/-6
That is our m
Our final equation is

If you apply the linear combination method to the system like:
<span>4(.25x + .5y = 3.75) → x + 2y = 15
(4x – 8y = 12) → x – 2y = 3
2x = 18
Then you can be sure that the solution of all this system is: (9,3). Hope this si what you were looking for</span>