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Lesson 6.1a – Writing the Equation of a Line. Concept: Writing Equations of Lines EQ: How do we write the equation of a line? (G.GPE.5) Vocabulary: Slope, y-intercept, point-slope formula. Rise Up Run Out. http://www.youtube.com/watch?v=rBAGAdySKSQ. Introduction.
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Lesson 6.1a – Writing the Equation of a Line Concept: Writing Equations of Lines EQ: How do we write the equation of a line? (G.GPE.5) Vocabulary: Slope, y-intercept, point-slope formula
Rise Up Run Out http://www.youtube.com/watch?v=rBAGAdySKSQ
Introduction Slope-Interceptform of an equation of a line is: Y = mx + b “m” represents the slope. “b” represents the y-intercept. You will use this form when you are given the slope and the y-intercept.
Slope – how steep a straight line is. = • Y-intercept – where the line crosses the y axis. Where x=0
Point-Slope Form of an equation of a line is: y = m(x – x1) + Where () is your given point and m is the given slope. Remember to distributeandsimplify!
Example 1 Write the equation of a line with a slope of 3 that crosses the y axis at (0, 2). Do we use Slope-Intercept or Point-Slope? How do you know?
Slope = m = ________ Y-intercept = b = ____________ Final equation of the line: _________________________
Example 2 Write the equation of a line with a slope of -2 that passes through the point (0,5). Do we use Slope-Intercept or Point-Slope? How do you know?
Slope = m = ________ Y-intercept = b = ____________ Final equation of the line: _________________________
You Try 1 You Try 2 Write the equation of a line with a slope of 5 that passes through the point (0, 3). Write the equation of a line with a slope of 3that passes through the point (0,6).
Example 3 Write the equation of a line that passes through points (2, 4) and (4, 6). Do we use Slope-Intercept or Point-Slope? How do you know?
Slope = m = = = = 1 Point (): (2, 4)
Example 4 Write the equation of a line that passes through points (3, 5) and (6, 11). Do we use Slope-Intercept or Point-Slope? How do you know?
Slope = m = = = = 2 Point (): (3, 5)
Example 5 Write the equation of a line that passes through points (2, 6) and (3, 10). Do we use Slope-Intercept or Point-Slope? How do you know?
Slope = m = = = = 4 Point (): (2, 6)
You Try 3 Write the equation for a line that passes through the points (2, 2) and (4, 5).
Example 6 Write the equation of this line.
Example 6 Y-intercept: (0, 4) b = 4 Slope = m = = = =2
Example 7 Write the equation of this line.
Example 7 Y-intercept: (0, 3) b = 3 Slope = m = = = =2
Example 8 Write the equation of this line.
Example 8 Y-intercept: (0, 6) b = 6 Slope = m = = = =-1
You Try 4! Write the equation for this line.
Ticket Out The Door 1. Write the equation of a line that passes through: (1, 5) and (6, 0) 2. Write the equation of a line with a slope of 3 that crosses the y-axis at (0, 3).