equations of lines geomtry 2017.notebook
January 31, 2017
1/31/17
Objective: How do we write the equation of a line given information about
the line?
DO NOW: USING YOUR GRAPHING CALCULATOR, GRAPH THE
FOLLOWING SETS OF LINES
y1 = 2x - 1
y2 = 2x + 4
1)
m = ___ b = ____
m = ____ b = _____
What is the relationship
between y1 and y2?
2) Graph both lines on the accompanying
graph.
1
equations of lines geomtry 2017.notebook
January 31, 2017
On the accompanying axes below graph the lines whose equations are:
y = 3x - 2 and y = -1/3x + 2
Let's use the slope intercept method.
x
y
What is the relationship between these two lines?
2
equations of lines geomtry 2017.notebook
January 31, 2017
General Form for an equation of a line:
Slope intercept form: ____________________
Slope Formula: ___________________________
Parallel Lines
Perpendicular Lines
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equations of lines geomtry 2017.notebook
January 31, 2017
Writing equations of lines:
Case I: parallel to a given line:
Example: Write an equation of a line parallel to the
line 2y = x - 6 and has a y intercept of 3.
Case II: Perpendicular to a given line:
Write an equation of a line that is perpendicular to the
line y = 3/4x + 2 and has a y intercept of -3
4
equations of lines geomtry 2017.notebook
January 31, 2017
Case III: Given a point
Example 3) Write an equation of a line that is parallel to the line
y = 3/2x - 6 and passes through the point (4,8)
4) Write an equation of a line that is perpendicular to the line
y = -1/2x -3 and passes through the point (1,-4)
5