A graph is simply a visual representation, that means graphing a linear function is simply creating a visual representation of the pattern it represents.[br][br]Linear Functions are patterns with a starting amount, and the output values (y-values) change by a constant addition or subtraction.
If it is the starting amount, what input number is it paired up with? For example if there is a pattern that starts at $100 and grows by $15 each week, what week number matches up with the initial $100?
If it is the starting amount, the input number is always 0. So, in the example, $100 matches up with week 0.
Where on the graph is the input 0?
Anywhere on the y-axis is a point when x = 0
[color=#ff0000][size=200]*[/size][/color]The starting amount on a graph is the y-intercept. And it is from this point that the pattern proceeds, through an addition or subtraction pattern. [br][br]This matches the [i]b[/i] number in our [math]y=mx+b[/math] equation. And since this is the starting amount it will be the first point that we will add to the graph.