4.6.notebook
December 16, 2014
p.253
4.6 Notes
LT: I can write and graph direct variation equations.
Two variables x and y show _____________________ Direct Variation when y = ax and a ≠ 0. The nonzero number a is called the ___________________________, and y is said to vary directly with x. Ex.
*Direct Variation is y = mx + b, where m = __ and b = __.
How do you 1. know if an 2. equation represents a 3. direct variation? Ex. 1
Ex. 2
2x ­ 3y = 0
­x + y = 4
4.6.notebook
December 16, 2014
Graph the direction variation equations:
*The graph of a direction variation equation always passes through ____________________.
2
y = x
3
y = ­3x
Write a direct variation equation that relates x and y.
Write a direct variation equation for the graph.
x = 2
y = 26
Summary:
4.6 CW
p.253­256 (GP #1­7)
1.
2.
3.
4.
5.
6.
7.
*read ex. 5
*read ex. 4
4.6.notebook
December 16, 2014
Match the equation with its graph.
1) 3x + 2y = 6
3) 3x ­ 2y = 6
2) 3x + 2y = ­6
4) 3x ­ 2y = ­6
A
B
C
D
Match the equation with its graph.
1) 3x + 2y = 6
3) 3x ­ 2y = 6
2) 3x + 2y = ­6
4) 3x ­ 2y = ­6
A
B
C
D
4.6.notebook
December 16, 2014
IF
Turn in Blue IF.
Grab the IF sheet for today.
4.6.notebook
December 16, 2014
Match the equation with its graph.
1) 3x + 2y = 6
3) 3x ­ 2y = 6
2) 3x + 2y = ­6
4) 3x ­ 2y = ­6
A
B
C
D
4.6.notebook
December 16, 2014
4.5 (day 2) CW
7. lines A and C are parallel
40ab.
42a.
c. $6
b. the difference is $50 no matter how many hours it takes to repair a car because the slopes are the same.
4.6.notebook
December 16, 2014
4.5 (day 2) answers
36. y = ­6x + 5, the equation has the same slope, but a different y­intercept.
38. ­23
44.
c. Larger booth, if he sells all of the pictures he would make $5500 instead of $3650 from the smaller booth.
4.6.notebook
December 16, 2014
check
check
check
check
ck
e
ch
SKIP 50
SKIP 35
SKIP 22,38
check
check
score?
SKIP 40, 42
4.6.notebook
December 16, 2014
4.6 Notes
p.253
LT: I can write and graph direct variation equations.
direct variation
Two variables x and y show _____________________ Direct Variation when y = ax and a ≠ 0. The nonzero number a is constant of variation
called the ___________________________, and y is said to vary directly with x. Ex.
*Direct Variation is y = mx + b, where m = __ and b = __.
How do you 1. Try to rewrite in the form y = ax
1. know if an 2. If y = ax is possible, it represents direct variation.
2. equation represents a 3. 3. Identify the constant of variation (a).
direct variation? 2x ­ 3y = 0
Ex. 1
­x + y = 4
Ex. 2
4.6.notebook
December 16, 2014
Graph the direction variation equations:
*The graph of a direction variation equation always passes through the origin (0, 0)
____________________.
2
y = x
3
y = ­3x
Write a direct variation equation for the graph.
Write a direct variation equation that relates x and y.
x = 2
y = 26
4.6.notebook
December 16, 2014
Summary:
Direct Variation y = ax a ≠ 0
All direct variation graphs pass through (0,0)
direct variation means y = mx + 0
4.6.notebook
December 16, 2014
4.6 CW p.253­256 (GP #1­7)
show all work!
1.
2.
3.
4.
Not direction variation
direct variation, a = ­2
direct variation, a = 4/5
5.
6.
7.
y = 1.5x, y = 36
125 tbsp
no, the equation that models this situation DOES NOT have the form y = ax.
4.6.notebook
December 16, 2014
4.6 answers
26. direct variation y = 5x
2r