## The effect of the sign of the slope in y = ax

A linear function is a function whose equation is of the form $y = ax + b$. We separate the discussion about it into two parts: $b = 0$ and $b \neq 0$. In this post, we only discuss the graph of $y = ax + b$ where $b = 0$. We discuss the effect of the sign of the slope in $y = ax$.

If we let $b = 0$, the equation $y = ax + b$ becomes $y = ax + 0$ or simply $y = ax$.

Notice that if $x = 0$, then $y = ax = a(0) = 0$. This means that the graph contains the point with coordinates $(0,0)$. Therefore, $y = ax$ passes through the origin.

Generalization 1: The graph $y = ax$ passes through the origin.

We now examine the effect of the values of $a$. There are three cases: $a = 0$, $a > 0$, and $a < 0$» Read more

For the past two months, I have been slowly updating my GeoGebra tutorials for GeoGebra 5.0. Several of the new updates include the series on GeoGebra Essentials.  The updates of other tutorial series will follow in the next few weeks.

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