sign of the slope Archives - Math and Multimedia

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

November 16, 2015 GB High School Algebra, High School Mathematics

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.