DATE
NAME
Homework -
PERIOD
Direct Variation
F'or Exercises 1-2, determine whether each linear function is a direct variation.
If
so, determine the
constant of variation.If not, explain why not.
1.
x
5
l0
15
20
v
0.41
0.82
1.23
1.64
k=!x
ls this linear function an example of direct variation?
lf yes, what is the constant of variation
lf no, explain why nol
2.
x
I
9
10
1l
v
3
4
5
6
k=Z
ls this linear function an example of direct variation?
lf yes, what is the constant of variation
lf no, explain why not.
For Exe(cisÇ34,
! varies directly with x. Write an equation for the direct variation. Then determine
each
value.
3, If y
:
12 when x
:
Determiney when x
6, write an equation for the direct variation (y
:
18 using your equation.
=
kx).
y=
4, If y: -4
when x
Determiney when
:
10, write an equation for the direct variation
¡ : 2 using your equation.
(y
-
kx)
y=
5.
What other method/strategy could you have used to solve #3 and#4?
Name
Period
Dtrect Varùat¿or,t Norkshee[
Write the direct variation formula
What is a called?
Where is the y-intercept of any direct variation equation?
1) circle the equation that is Nor an example of direct variation
A) y=
2)
_1
Jx+I
B)
v-ar
t6
D)y=-gx
C)y = 4x
Circle the equation that is a direct variation equation.
A)y=7-3x
B)3x-7y=1
C)3x-7y=6
D) 3y
=7x-
1
3) What is the direct variation equation if y = 6 and x = 4?
4) What is the direct
variation equation if y
- -5
and x = 7?
For $7, the graph of a direct variation is shown. a) write the direct variation equation for
the
graph. b) Determine the value of y when x = g using your equation.
5)
6)
7)
I
v
5t
a)
a)
a)
b)
b)
b)
B) Suppose y varies directly with x' and when y is 16, x is
the data. b) Find y when x is 16.
I.
a) write the direct variation equation for
a)
b)
9)
Suppose y varies direcfly with x, and when y is2,x is
3 a) Write the direct variation equation
for
the data. b) Find x when Vís 42.
a)
b)
l?l
ä:ïH:Jiiii:1îî::i
murrins carrs ror 3 cups or nour.
rhe number or murrins varies direcry
a) write a direct variation equation for the relationship between
the number of
cups of flour and muffins. (Hint, cannot use rhe number
2 in the equation.)
b) Use the-equation to determine how many cups of flour are needed
to make 6
dozen muffins.
1 1) Your distance.ftom a lightning
bolt varíes directly with the time it takes you
to hear thunder. lf
you hear thunder 10 seconds aftei you see
the lightríing, you are about 2 miles from the
lightning.
a) Write a direct
b)
variation equation for the relationship between
time and distance.
How many seconds it willtake for the thunder to
travel a af 4miles.