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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
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 Outhttp://www.youtube.com/watch?v=rBAGAdySKSQ
IntroductionSlope-Intercept form 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 distribute and simplify!
Example 1Write 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?
𝑦=𝑚𝑥+𝑏Slope = m = ________Y-intercept = b = ____________
Final equation of the line:_________________________
Example 2Write 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?
𝑦=𝑚𝑥+𝑏Slope = m = ________Y-intercept = b = ____________
Final equation of the line:_________________________
You Try 1 You Try 2Write the equation of a line with a slope of 3 that passes through the point (0,6).
Write the equation of a line with a slope of 5 that passes through the point (0, 3).
Example 3Write 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?
𝑦=𝑚 (𝑥−𝑥1 )+𝑦1Slope = m = = = = 1
Point (): (2, 4)
Example 4Write 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?
𝑦=𝑚 (𝑥−𝑥1 )+𝑦1Slope = m = = = = 2
Point (): (3, 5)
Example 5Write 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?
𝑦=𝑚 (𝑥−𝑥1 )+𝑦1Slope = m = = = = 4
Point (): (2, 6)
You Try 3Write the equation for a line that
passes through the points (2, 2) and (4, 5).
Example 6Write the equation of this line.
Example 6Y-intercept: (0, 4)
b = 4
Slope = m = = = =2
Example 7Write the equation of this line.
Example 7Y-intercept: (0, 3)
b = 3
Slope = m = = = =2
Example 8Write the equation of this line.
Example 8Y-intercept: (0, 6)
b = 6
Slope = m = = = =-1
You Try 4!Write the equation for this line.
Ticket Out The Door1. 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).
