Question 6310
In these kinds of problems, you assign values of your own choosing to x (the independent variable) and then you compute the corresponding value of y (the dependent variable).  You can then make what is called an input-output table showing these values.  It makes things a little easier if you first solve the equation for y by putting it into the slope-intercept form, y = mx + b.

We'll do this for this equation, 2x + 5y = 8

2x + 5y = 8  Subtract 2x from both sides.
5y = -2x + 8 Divide both sides by 5
y = (-2/5)x + 8/5

Now set up the input-output table. The x-value that you assign corresponds to the input and the resulting y-value is the output.

x,     y
--------
0,    8/5
1,    6/5
2,    4/5
-1,   10/5
-2,   12/5

Of course, you need only two points to define a straight line but you can calculate any number of points you wish.

Now, on a piece of graph paper on which you have drawn the x-axis (horizontal) and the y-axis (vertical), you can graph some or all of the points in the table and then join them together with a straight line.  It should look like the graph shown below: 



{{{graph(300,200,-10,10,-10,10,(-2/5)x+8/5)}}}