Transcript Finding X and Y intercepts

Warm-up
Make a T-Table and graph the equation
y = 2x + 2
x
y
-2
-2
0
-1
0
1
2
2
4
6
Finding X and Y
intercepts
What is an intercept?
y
5
Where the line
(0, 3)
crosses the y-axis.
y-intercept = 3
(4, 0)
x-intercept = 4
x
Where the line
crosses the x-axis.
-5
-5
5
In your notes:
1.)
y
5
(0, 3)
y-intercept = 3
(3, 0)
x
x-intercept = 3
-5
-5
5
In your notes:
2.)
y
5
y-intercept = -4
(-1, 0)
x
x-intercept = -1
(0, -4)
-5
-5
5
X and Y Intercepts
Plug in 0 for y – this is the x-intercept
Plug in 0 for x – this is the y-intercept
Finding X intercepts
x+y=5
x + (0) = 5
y
5
x =5
x =5
(5, 0)
-5
-5
5
x
Finding X intercepts
x - 3y = 7
x - 3(0) = 7
y
5
x =7
x =7
(7, 0)
x
-5
-5
5
Finding X intercepts
6x + 12y = 36
6x + 12(0) = 36
y
5
6x = 36
6
6
(6, 0)
x
x =6
-5
-5
5
Finding Y intercepts
y = -3x - 4
y = -3(0) - 4
y
5
y = -4
y = -4
x
(0, -4)
-5
-5
5
Finding Y intercepts
-3x + 6y = 18
-3(0) + 6y = 18
6y = 18
6
6
y
5
(0, 3)
y =3
x
-5
-5
5
Finding Y intercepts
y=½x+6
y = ½ (0) + 6
(0, 6)
y
5
y =6
y =6
x
-5
-5
5
Finding X and Y intercepts
2x + 3y = 6
2x + 3(0) = 6
2x = 6
2
2
x =3
y
5
(0, 2)
(3, 0)
2x + 3y = 6
2(0) + 3y = 6
3y = 6
3
3
y =2
-5
-5
5
x
Finding X and Y intercepts
4x + 8y = 16
4x + 8(0) = 16
4x = 16
4
4
x =4
y
5
(0, 2)
(4, 0)
4x + 8y = 16
x
4(0) + 8y = 16
8y = 16
8
8
y =2
-5
-5
5
Finding X and Y intercepts
x - 2y = 4
x - 2(0) = 4
x = 4
y
5
x =4
(4, 0)
x - 2y = 4
(0) - 2y = 4
-2y = 4
-2 -2
y = -2
x
(0, -2)
-5
-5
5
Finding x and y intercepts
Find the x-intercept of the line
- 3x + 2y = 9
X-intercept MEANS y = 0
Finding x and y intercepts
Find the y-intercept of the line
- 3x + 2y = 9
y-intercept MEANS x = 0
Cover
method
Hint: Cover up
Hint:up
Cover
up
2x this
Solvethe
for
x
and
time.
y.
the 4y first.
2x + 4y = 8
2x + 4y = 8
2x = 8
4y = 8
y
5
x=4
y=2
x
-5
-5
5
Use the Cover Up Method
- 6x – 4y = 2
-6x = 2
x = -1/3
-6x – 4y = 2
-4y = 2
y= -1/2
y
5
x
-5
-5
5
(-1/3, -1/2)