3 6 Lines in the Coordinate Plane Objectives

3 -6 Lines in the Coordinate Plane Objectives Graph lines and write their equations in slope -intercept form. Classify lines as parallel, intersecting, or coinciding. Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Vocabulary point-slope form slope-intercept form Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Example 1 A: Writing Equations In Lines Write the equation of each line in the given form. the line through (– 1, 0) and (1, 2) in slopeintercept form Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Example 1 B Write the equation of each line in the given form. the line with slope 0 through (4, 6) in slopeintercept form Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Example 2 A Graph each line. y = 2 x – 3 Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Example 2 B Graph each line. y = – 3 Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane A system of two linear equations in two variables represents two lines. The lines can be parallel, intersecting, or coinciding. Lines that coincide are the same line, but the equations may be written in different forms. Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Example 3 A: Classifying Pairs of Lines Determine whether the lines are parallel, intersect, or coincide. y = 3 x + 7, y = – 3 x – 4 Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Example 3 B: Classifying Pairs of Lines Determine whether the lines are parallel, intersect, or coincide. Holt Mc. Dougal Geometry

3 -6 Lines in the Coordinate Plane Example 4: Problem-Solving Application Erica is trying to decide between two car rental plans. For how many miles will the plans cost the same? Holt Mc. Dougal Geometry