Direct Variation

Write an equation

100

In a direct variation, y=12 when x=4.

Write a direct variation equation that shows the relationship between x and y.

y=3x 

200

In a direct variation, y=–20 when x=20.

Write a direct variation equation that shows the relationship between x and y.

y=-x

300

Question

In a direct variation, y=69 when x=23

   Write a direct variation equation that shows the relationship between x and y.

y = 3x

400

Question

In a direct variation, y=16.8 when x=4 

Write a direct variation equation that shows the relationship between x and y.

y = 4.2x

500

In a direct variation, y=7/6 when x=4/3.

Write a direct variation equation that shows the relationship between x and y. 

y = 7/8x

Write and solve

100

If y varies directly with x and y=15 when x=5, find y when x=1.

3

200

A direct variation includes the points (5,15) and (3,n). Find n.

9

300

If y varies directly with x and y=72 when x=6,find x when y=48.

4

400

If y varies directly with x and y=

18.72 when x=1.6, find y when x=1.

11.7

500

If y varies directly with x and y=6/7 when x=3/2 find x when y=3/7.

3/4