Review of Slope
and y-intercept
Slope is a
measure of
Steepness.
Types of Slope
Zero
Negative
Positive
Undefined
or
No Slope
Slope is sometimes
referred to as the
“rate of change”
between 2 points.
If given 2 points on
a line, you may find
the slope using the
formula
𝑦2 − 𝑦1
𝑚=
𝑥2 − 𝑥1
Find the slope of the
line through the
points (3,7) and (5, 19).
x1 y1
x2 y2
m = 19 – 7
5–3
m = 12
2
m=6
(3, 4) and (-6, -2)
m = -2 – 4
-6 – 3
m = -6
-9
m=⅔
What if the
numerator is 0?
What if the
denominator is 0?
0 denominator or Numerator
 If the denominator of the fraction is 0, the slope is
undefined. This occurs if the x value is the same for both
points.
 The graph would be a vertical line and would
indicate that the x value stays constant for every
value of y.
 If the numerator of the fraction is 0, the slope is 0.
 The graph would be a horizontal line and would
indicate that the y value stays constant for every
value of x.
Finding Slope using slopeintercept form
If given a point on the line and its
slope, the equation of a line is
typically written as
y = mx + b where m is the slope
and b is the y-intercept
What is the slope and
y-intercept of the
following equation?
y = 3x + ½
slope (m) = 3
y-intercept (b) = ½
Write the slope-intercept form equation of
the lines with the given slope and y
intercepts.
 1. slope = -3/4, y-intercept = 7
 2. slope = 2, y-intercept -1
 3. slope = -2, y-intercept = 2
Write the slope-intercept form equations of
the lines with the given slope and y
intercepts.
 1. y = -3/4x + 7
 2. y = 2x – 1
 3. y = -2x + 2
Finding Slope using standard
form
Another method to
find the slope if given
an equation of a line
is to write the equation
in the form Ax + By = C.
m = -A/B,
b = C/B
3x + 5y = 10
First, solve the equation for y.
3x + 5y = 10
5y = -3x + 10
y = -3/5 x + 2
m= -3/5
b=2
Find the slope and
y-intercept of the
following equations.
8x + 11y = 7
Solve for y!
y = -8/11x + 7/11
m= -8/11
b = 7/11
-6x = 2y + 14
Solve for y!
y = -6/2 – 14/2
m= -6/2
m= -3
b = -14/2
b = -7
Finding Slope using
triangle method
If given the graph
of a line, find the
slope by using the
“triangle” method to
find the rise over run.
rise = 4
m= rise
run
run = 5
m= 4/5
The
End