Chapter 7 Unit Question What are the components and applications of lines on the coordinate plane? Open Learning Logs Date on LeftSection 7 4 on right WITHOUT ACTUALLY GRAPHING THESE LINES, please describe in words HOW you would graph each line and some characteristics of each WARM UP 7 4 ( 3, -8 ) Point Slope ( -3, 0 ) Point Slope ( 0, 0 ) Point Slope Section 4 How do we find the equation for a line given its slope and point? Homework Clicky Point-Slope Definition Point-Slope form for the equation of a line. y y 1 = m(x x 1 ) Equation of a non-vertical line with slope m and point (x 1, y 1 ) is y - coordinate slope x - coordinate Bottom Line: Just substitute! A line passes through (4, 2) and has a slope of . Whats the equation? y y 1 = m(x x 1 ) (x 1, y 1 ) m y 2 = (x 4) A line passes through (-3, 6) and has a slope of -5 Whats the equation? y y 1 = m(x x 1 ) (x 1, y 1 ) m y 6 = -5(x -3) y 6 = -5(x + 3) Graphing ( 2, 1 ) Point Slope Slope is a DIRECTIONit points to the next point on a line! Start at the given point Then SAY the slope +U 2 OVER 3 That is our direction to the next point. Up 2 Over 3 Graphing ( -4, 3 ) Point Slope Slope is a DIRECTIONit points to the next point on a line! What is the graph of the equation y 3 = -4(x + 4) Start at the given point Then SAY the slope -D 4 OVER 1 That is our direction to the next point. Down 4 Over 1 Down 4 Over 1 What is the equation of the line in point-slope form? Find Slope first! Now go to point-slope form! y y 1 = m(x x 1 ) Pick a point and substitute! y 4 = (x 1) (1, 4) (-2, -3) The table shows the descent of a hot air balloon. timealtitude xy What is the equation of the line that represents the descent? y y 1 = m(x x 1 ) y 640 = 2.5 (x 10) Fantastic! Now solve for y! y 640 = 2.5x y = 2.5x This form is called the Slope-Intercept form Well be talking more about this tomorrow! Homework Do HoffmaSheet 7 4