Plotting linear functions is very easy. You do not need to go to
the advanced section of this lesson. A
linear function is
always represented by a straight line, which you always
should plot with a ruler.
All you need to plot a linear function is to determine its value at
two points. Even though, mathematically speaking, these two points can
be arbotrarily close, if you choose them to be too close, your line
may deviate from what the graph really is. So try to choose your
points so that they would be relatively far on the graph.
Let's assume that the function you want to plot is
y=ax+b, where a and b are two numbers
Your first task is to determine where it intersects the x and y
axis. The intersection with the y axis is the point with the x
coordinate 0 and the y coordinate being a*0 + b, that is, b. So the
point is (0, b).
The intersection with the x axis is the point (x, 0) where the
value of ax + b = 0. To find that x, you just need to set ax+b=0, and
you get x = -b/a. A caveat: if a is zero, you should not try to find
the intersection with the x axis this way, because you cannot divide b
by zero. For equations y = 0x + b, you just draw a straight horizontal
line through point (0, b).
Graph of y = 0*x + 2, a = 0 so it is a horizontal line. No
intersection with the x axis.
Graph of y =
Once you have these two points marked, take a ruler and draw the
line through them. You are done.