Transcript Graphing Linear Equations - Clovis Municipal School District

Graphing
Linear
Equations
Linear Equation
An equation for
which the graph is
a line
Solution
Any ordered pair of
numbers that
makes a linear
equation true.
(9,0) IS ONE SOLUTION
FOR Y = X - 9
Linear Equation
Example:
y=x+3
Graphing
Step 1:
~ Three Point Method ~
Choose 3 values for
x
Graphing
Step 2:
Find solutions using table
y=x+3
X | Y
0
1
2
Graphing
Step 3:
Graph the points
from the table
(0,3) (1,4) (2,5)
Graphing
Step 4:
Draw a line to
connect them
Try These
• Graph using a table (3 point
method)
1) y = x + 3
2) y = x - 4
Slope-Intercept
y = mx + b
m = slope
b = y-intercept
Slope-Intercept
• The m in the slope-intercept form is
ALWAYS attached to the X variable.
• The slope is NEVER including the X
variable
• For example, if given y = 3x + 4 the slope
is 3 NOT 3x.
Y-intercept
Where the line
crosses the
y-axis
Y-intercept
The y-intercept has
an x-coordinate of
ZERO
Y-intercept
To find the yintercept, plug in
ZERO for x and
solve
Y-Intercept Summary
• The y-intercept is the b in the slope
intercept form.
• This b (y-intercept) is your starting point
on the graph.
– To easily remember this, think of b as you
Beginning point.
• For example, in y = 3x + 4 the Beginning
point is at (0,4) {Remember: to find the yintercept, plug on zero for the x.}
X-intercept
Where the line
crosses the
x-axis
X-intercept
The x-intercept has
a y coordinate of
ZERO
X-intercept
To find the xintercept, plug in
ZERO for y and
solve
Slope
Describes the
steepness of a
line
Slope
Equal to:
Rise
Run
Rise
The change
vertically, the
change in y
Run
The change
horizontally or
the change in x
Finding Slope
Step 1:
Find 2 points on
a line
(2, 3) (5, 4)
(x , y ) (x , y )
1
1
2
2
Finding Slope
Step 2:
Find the RISE
between these 2
points
Y-Y =
2
1
4-3=1
Finding Slope
Step 3:
Find the RUN
between these 2
points
X-X =
2
1
5-2=3
Finding Slope
Step 4:
Write the RISE over
RUN as a ratio
Y-Y
2
1
X-X
2
1
=
1
3
Step 1:
Mark a point on
the y-intercept
Step 2:
Define slope as
a fraction...
Step 3:
Numerator is the
vertical change
(RISE)
Step 4:
Denominator is
the horizontal
change
(RUN)
Step 5:
Graph at least 3
points and
connect the
dots