Determine the relationship of two linear functions

Given two straight lines (from two linear functions), we can categorize their relationship.  Options are:

  • Parallel & distinct (two separated parallel lines)
  • Parallel & coincident (two parallel lines on top of each other)
  • Perpendicular (two lines intersecting and forming a 90 degrees angle at the point of intersection)
  • Intersecting (intersecting and not forming any particular angle)

Here the relationships are illustrated through graphs.  But we will not determine the relationship by graphing because graphs are inherently imprecise.  Instead, we will learn to determine the relationship by comparing slope and y-intercept values.

Step 1: Determine the slope and y-intercept of a linear function

Step 2: Determine the relationship by comparing the slopes and y-intercepts

Extra practice

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