# Day Problems Graph each equation.

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Day Problems Graph each equation.
1. y – 2 = (x – 3) 2. y + 3 = -2(x – 1) Write an equation in point-slope form for the line through the given point with the given slope. 3. (4 , 2); m = (-5 , 2); m = 0 A line passes through the given points. Write an equation for the line in point-slope form. Then rewrite the equation in slope-intercept form. 5. (-1 , 0) , (1 , 2)

6.5 Parallel and Perpendicular Lines 2/22/11
Parallel lines – lines in the same plane that never intersect.

Slopes of Parallel Lines
Nonvertical lines are parallel if they have the SAME SLOPE and DIFFERENT Y-INTERCEPTS. Any two vertical lines are parallel. Example – The equations y = 2x + 1 and y = 2x + 3 have the same slope, 2, and different y-intercepts. The graphs of the two equations are parallel.

Determining Whether Lines are Parallel
Are the graphs of and 2x + 6y = 12 parallel? Explain. Write 2x + 6y = 12 in slope-intercept form. Then compare with The lines are parallel. The equations have the same slope, , and different y-intercepts.

Writing Equations of Parallel Lines
Write an equation for the line that contains (5 , 1) and is parallel to Step 1 – Identify the slope of the given line. Step 2 – Write an equation of the line through (5 , 1) using point-slope form, then change to slope-intercept.

Perpendicular Lines 2/23/11
Perpendicular lines – lines that intersect to form right angles. SLOPES OF PERPENDICULAR LINES Two lines are perpendicular their slope is the opposite reciprocal of the given slope. A vertical and horizontal line are also perpendicular. EXAMPLE – the slope of is The slope of y = 4x + 2 is 4.

Opposite Reciprocal How to find the opposite reciprocal of a number:

Writing Equations for Perpendicular Lines
Find an equation of the line that contains (0 , -2) and is perpendicular to y = 5x + 3. Step 1- Identify the slope of the given line. m = 5 Step 2 – Find the opposite reciprocal of the slope: Step 3 – Use the slope-intercept form to write an equation.

More Practice!!! Textbook – p. 314 #2 – 30 even.
Homework – Worksheet 6.5.