Graph 3y – 3x = -15 and 6y – 12x = 12 on the same coordinate plane Graph 3y – 3x = -15 and 6y – 12x = 12 on the same coordinate plane. State two ways the graphs are different. Explain the reason for each difference. Sample Answer: 1.) The graph of the line y = x – 5 will be less steep than the graph of the line y = 2x + 2. This is because the slope of the line y = x – 5 is 1 and the slope of the line y = 2x + 2 is 2. If the slope is greater, the line is steeper. 2.) The graph of the line y = x – 5 will cross the y-axis at -5 and the graph of the line of y = 2x + 2 will cross the y-axis at 2. This is because the y-intercept of y = x – 5 is -5 and the y-intercept of y = 2x + 2 is 2.
y = -2/3x + 2 y = -2/3x – 3 Parallel lines have the same slope. 1. On one square, graph the lines: y = -2/3x + 2 y = -2/3x – 3 What are these lines called? What can you conclude about these lines and their slope? Parallel lines have the same slope. The slope of line 1 = -2/3 The slope of line 2 = -2/3 Parallel lines have the same slope.
Fri, 1/11 SWBAT…Write equations that are parallel or perpendicular Agenda WU (10 min) Parallel and perpendicular lines (35 min) Warm-Up: Directions: Find the slope of the line parallel to each given line. y = 3x – 2 -5y = 8x + 6 -2y – 5x = 10 HW#7: Parallel and perpendicular lines (both sides) 3
Write an equation in slope-intercept form (y = mx + b) for the line that is PARALLEL to y = -3/4x + 4 and that passes through the point (-2, 3). Graph BOTH LINES.
2. On one square, graph the lines: y = 4x + 2 y = -1/4x – 3 What can you conclude about perpendicular lines and their slope? Perpendiculars lines have slopes that are opposite signs and reciprocals!!!!!! The slope of line 1 = 4 The slope of line 2 = -1/4 Perpendiculars lines have slopes that are opposite signs and reciprocals. In other words, when you multiply their slopes, they equal -1.
Are y = 3 and y = 7, parallel, perpendicular or neither? Answer: Parallel, because they have the same slopes of 0 (they are horizontal lines.)
y = -5/2x + 10 -5x + 2y = 20 Are these two lines parallel, perpendicular or neither? Answer: Neither. The first line has a slope of -5/2 and the second line has a slope of 5/2. They do not have the same slope or opposite and reciprocals.
y = 1/3x + 10 3x + y = 5 Are these two lines parallel, perpendicular or neither? Answer: Perpendicular. The first line has a slope of 1/3 and the second line has a slope of -3. They have slopes that are opposite and reciprocals, therefore they are perpendicular lines.
Are x = 4 and x = 7parallel, perpendicular or neither? Answer: Parallel, because they have the same slopes of undefined(they are vertical lines)
Write an equation in slope-intercept form (y = mx + b) for the line that is PERPENDICULAR to the given line and that passes through the given point. Graph BOTH LINES. y = -½x (-2, 0)
Mon, 1/14 SWBAT…Write equations that are parallel or perpendicular Agenda WU (10 min) Parallel and perpendicular lines (40 min) Warm Up: Take out HW#7: Parallel and Perpendicular lines Write your HW in your planners for the next TWO weeks – week 18 AND week 19! Write the equation in slope-intercept form for the line that is PERPENDICULAR to y = 1/3x and passes through ( -2, 0). Graph both lines. HW#7: Parallel and perpendicular lines (both sides) 11
Discuss in your tables… How can you write the equation of the line in slope-intercept form (y = mx + b) for the line that is PERPENDICULAR to y = -5x and that passes through point (0, 3).