Notes with answers - Summit Schools

Your Notes
Homework
y 2 y 1 5 m(x 2 x 1 ) Use point-slope form.
y 2 1 5 22 [x 2 (21) ] Substitute 1 for y 1 , 22
for m, and 21 for x 1 .
y 2 1 5 22x 2 2 Distributive property
y 5 22x 2 1 Slope-intercept form
Example 4 Write Equations of Perpendicular Lines
Write an equation of the line that passes through
(23, 5) and is perpendicular to the line y 5 4x 2 1.
solution
The given line has a slope of 4 . The slope of any
line perpendicular to this line will be the negative
reciprocal of 4 , which is 2 1
} .
4
Use point-slope form with (x1 , y1 ) 5 (23, 5) and
m 5 2 1
} to write the equation of the line.
4
y 2 y 1 5 m(x 2 x 1 ) Use point-slope form.
y 2 5 5 2 1
} [x 2 (23) ]
4
Substitute 5 for y1 , 2 1
}
4
for m, and 23 for x1 .
1
y 2 5 5 2 } x 2
4 3
}
4
Distributive property
1
y 5 2 } x 1
4 17
}
4
Checkpoint Write an equation of the line.
3. The line through
(22, 3) parallel to
y 5 4x 2 6
y 5 4x 1 11
Slope-intercept form
4. The line through
(22, 3) perpendicular
to y 5 4x 2 6
y 5 2 1
} x 1
4 5
}
2
Copyright © McDougal Littell/Houghton Mifflin Company Lesson 2.5 • Algebra 2 C&S Notetaking Guide 39