Direct and Inverse Variation

Direct Variation

100

If y = 12 when x = 17, find y when x = 34

y = 24

200

Find the missing variable of Direct Variation (2,y) and (10,15)

y= 3

300

Find the missing variable of Direct Variation (2/3, 2) and (x,6)

x=2

400

If y = 1/8 when x = 2/9, find y when x = 6/9

y = 3/8

500

The amount of simple interest earned in a savings account varies directly with the amount of money in the savings account. You have $1000 in your savings account and earn $30 in simple interest. How much interest would you earn if you had $1500 in your savings account.

You would earn $45 in simple interest.

Inverse Variation

100

If y varies inversely with x, write and equation. x=9 and y=4

y=36/x

200

if y = 7 when x = 9, find y when x =21

y = 3

300

Find the missing variable in this inverse variation (4,28) and (7, p)

p=16

400

Find the missing variable in this inverse variation (3/4,y) and (2/3,18)

y=16

500

Find the missing variable in this inverse variation. (12.5,6.5) and (f,3.25)

f= 25

Solve for the Constant

100

Find the Constant: 

x:   2,   7, 10 

y: 35, 10, 7

K=70

200

Find the Constant: 

x: 1.2, 1.5, 2.4 

y:    5,    4, 2.5

K=6

300

Find the Constant: 

x:    2,     3,      10 

y:    4.5,  6.75, 22.5

k=2.25

400

Find the Constant: 

x: 2, 8, 16 

y: 9, 36, 72

k=4.5

500

Find the Constant: 

x: 0, 2, 4, 6 

y: 3, 5, 7, 9

There is no constant, this is not direct or inverse variation.

Create a Table

100

y= 2x When x: 1, 2, 3

y: 2, 4, 6

200

y= 3x - 2 When x: 1, 2, 3

y: 1, 4, 7

300

y= x² + 1 When x: -2, -1, 0, 1, 2

y: 5, 2, 1, 2, 5

400

y= (1/2) * x When x: 1, 2, 3

y: 1/2, 1, 1 1/2

500

y= -|x| - 1 When x: -2, -1, 0, 1

y: -3, -2, -1, -2