Direct Variation and Functions

 y varies directly with x, and y is 84 when x is 16. What is the constant of proportionality?

• y = (21/4)x

• k= 21

• k= 5.25

• k= 4/21

Is this a direct variation?
y=2x

• yes

• no

Write the equation for the table given.

• y = 1/3x

• y = 3x

• y = 1/2x

Is this a direct variation?

• yes

• no

Does the following represents direct variation?

• Yes

• No

Does the following represents direct variation?

• Yes

• No

Is this a direct variation?

• yes

• no

Which set of values is a function?

• (9,5) (10,5) (9,-5) (10,-5)

• (3,4) (4,-3) (7,4) (3, 8)

• (6,-5) (7, -3) (8, -1) (9, 1)

• (2, -2) (5, 9) (5, -7) (1, 4)

Which of these tables represent a function?

• A

• B

• C

• D

Does the mapping of these points represent a function?

• Function

• Not a Function