Do Now:
6. Find the equation of the line with slope
and passing throught the point (-3, 4).
2
5
7. Find an equation of the perpendicular bisector
of the segment joining (-2, 8) and (1, 12).
3.2 Slope-Intercept and Intercept Forms
Slope-Intercept Form y = mx + b,
m = slope
b = y-intercept
Example 1: Find an equation of the line with
slope 2 and y-intercept 5
.
Intercept Form:
x
a
+
y
b
=1
a = x-intercept, b = y-intercept
Example 2: Find an equation of the line with x
and y intercepts 5 and -2
.
Example 3: Put the equation 2x - 3y - 6 = 0 into
Intercept Form and sketch.
y
10
9
8
7
6
5
4
3
2
1
0
-1 0 -9 -8 -7 -6 -5 -4 -3 -2 -1
-1
-2
-3
-4
-5
-6
-7
-8
-9
-1 0
1
2
3
4
5
6
7
8
9 10
x
Example 4: Put the equation 2x - 3y - 6 = 0 into
Slope-Intercept Form and sketch.
y
10
9
8
7
6
5
4
3
2
1
0
-1 0 -9 -8 -7 -6 -5 -4 -3 -2 -1
-1
-2
-3
-4
-5
-6
-7
-8
-9
-1 0
1
2
3
4
5
6
7
8
9 10
x
So 2x - 3y - 6 = 0 is the same as y =
2
3
x-2
For equations in General Form
Ax + By + C = 0, slope = -
A
B
, y-intercept = -
C
B
Example 5: Find the equations of the lines that are
(a) parallel and (b) perpendicular to
3x + 2y - 5 = 0 and contains the point (3, 1)
.