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Geometry Notes Name ______________________________ 2.9A Parallel and Perpendicular Lines Date ________________ Period ______ Objectives Classify lines as parallel, perpendicular, or intersecting. Pairs of Lines Parallel Lines Perpendicular Lines Intersecting Lines Relationship Example Decide whether the lines are parallel, perpendicular, or neither. ** You will sometimes need to first: solve the equations for y, and then: identify the slopes to answer the problem. Example 1: y = 3x + 7 y = –3x – 4 Example 2: 𝑥 + 3𝑦 = 5 6𝑦 = −2𝑥 + 12 Example 3: 2y – 4x = 16 y – 10 = 2(x - 1) Example 4: 3x + 5y = 2 3x + 6 = -5y Example 5: 2y = 4x + 12 4x – 2y = 8 State what the slope would be for a parallel line and for a perpendicular line to the given line. ** You may need to first solve the equation for y in order to identify the slope. Example 6: Example 7: Example 8: 3x + 5y = 2 y – 5 = 2(x + 3) 3x + 6 = -5y Example 9: Find the slope and the y-intercept of each line to write the equation of the line in slope-intercept form.