Comparing lines
Let f(x) = ax + b, and g(x) = cx + d, where a, b, c, and d, are any real numbers.
If f(x) and g(x) are graphed, what can you conclude about a, b, c, and/or d, if:
a. f(x) and g(x) are parallel?
b. f(x) and g(x) are perpendicular?
c. f(x) does not cross the xaxis?
d. g(x) is horizontal?
e. f(x) and g(x) have the same yintercept?

Related External Resources 
Graphing a Line [ java applet ]
This is an interactive step by step guide to graphing a line by using the yintercept and another point on the line.
General Form Linear Equations
Graph a series of lines in standard form using an interactive grapher, and observe patterns in the relationship between the graph and the equation. You can also predict the equation of a line from its graph.

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