11/4/2016
Prebell
Workbook p. 26 – 27 # 11, 13
Which lines are parallel?
How do you know?
Which lines are perpendicular?
How do you know?
Horizontal & Vertical Lines
• Lines only cross one axis, so equations only
have one variable.
– The axis crossed is the variable in the equation.
– The point where the line crosses the axis is the
number in the equation.
𝑥 = 14
Line crosses the ____-axis at _____.
𝑦 = −11
Line crosses the ____-axis at _____.
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Horizontal & Vertical Lines
HOY VUX
H: horizontal line
O: zero slope
Y: graph crosses the y-axis
V: vertical line
U: undefined slope
X:graph crosses the x-axis
𝑦 = −8
HOY
VUX
______________ line
___________ slope
Crosses ____ -axis at _____
𝑥=7
𝑥 = −5
HOY
HOY
VUX
VUX
______________ line
___________ slope
Crosses ____ -axis at _____
______________ line
___________ slope
Crosses ____ -axis at _____
𝑦=9
HOY
VUX
______________ line
___________ slope
Crosses ____ -axis at _____
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Writing Equations from Graphs
To write an equation in slope-intercept
form, you need to know the ____________
and ________________.
If given m and b:
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• 𝑚 = 3 , 𝑏 = −4
• 𝑚 = −7, 𝑏 = 11
Find the equation of the line
graphed below.
• Find the y-intercept.
If given a graph:
• Find the y-intercept.
• Find the slope.
• Plug these into
𝑦 = 𝑚𝑥 + 𝑏.
Writing Equations from Graphs
If the line doesn’t have slope:
• Which axis does the line
cross?
• Find the slope.
• At what point?
• Plug these into
𝑦 = 𝑚𝑥 + 𝑏.
Find the equation of the line graphed
below.
Find the equation of the lines
graphed below.
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If given a graph:
Writing Equations from Graphs
Writing Equations from Graphs
Writing Equations from Graphs
Writing Equations from Graphs
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11/4/2016
Writing Equations from Graphs
Writing Equations from Graphs
Writing Equations from Graphs
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