Download Chapter 4: Linear Equations

F-IF.B.4: Using Intercepts of
Linear Equations
F-IF.4 Using Intercepts
Definitions
Intercept: where two lines intersect.
x-intercept: where a point or line crosses
the x -axis.
y-intercept: where a point or line crosses
the y -axis.
F-IF.B.4 Using Intercepts
• The idea behind graphing a linear
equation using intercepts is to graph a
line you need two points.
• So we find and graph the x and y
intercepts of the linear equation.
F-IF.B.4 Using Intercepts
To find the x-intercept, y has to equal
zero.
(x, 0)
To find the y-intercept, x has to equal
zero.
(0, y)
F-IF.B.4: Intercepts Method
Step 1: Write equation in
Standard Form
Ax + By = C
Examples:
5x + 6y = -60
3x - 4y = 24
F-IF.B.4: Intercepts Method
Step 2:
• Find the x-intercept:
By setting the y value equal to zero and
then solve for x.
(x, 0)
F-IF.4: Intercepts Method
Step 3:
• Find the y-intercept:
By setting the x value equal to zero and
then solve for y.
(0, y)
F-IF.B.4: Intercepts Method
Step 4: Plot coordinates
x
Y
x
0
0
y
 x, y 
y
x
F-IF.B.4: Intercepts Method
Step 1: Write equation in:
Step 2: Find x intercept
2 x  3 y  6
y=0
2 x  3 y  6
2 x  3(0)  6
2 x  6
2 2
x  3
(3 , 0)
F-IF.B.4: Intercepts Method
Step 3: Find y intercept
x=0
2 x  3 y  6
2(0)  3y  6
3 y  6
3 3
y  2
(0 ,  2)
F-IF.B.4: Intercepts Method
 x, y 
Step 4: Plot coordinates:
x
Y
-3
0
0
-2
2 x  3 y  6
y
3
1
-3
-1
-1
-3
1
3
x
F-IF.B.4: Intercepts Method
Example:
x- int
x y 5
y=0
x  y 5
x  (0 )  5
x5
(5 , 0)
y -int
x=0
x y5
(0)  y  5
y5
(0 , 5)
F-IF.B.4: Intercepts Method
Plot coordinates of:
x
Y
5
0
0
5
x y5
x y5
y
8
4
-8
-4
4
-4
-8
8
x