Draw the graphs of the following sets of lines.
 
In each case, reflect on the role of \(a\) and \(b\).
 
\(y = 4x, y = 2x, y = x\)
 
Graph:
 
 
Role of \(b\):
 
In all three equations, . This means all lines pass through the point .
 
Role of \(a\):
 
All slopes are positive , so they all rise from left to right. As \(a\) increases from  to  , the lines become   (closer to the y-axis).