Direct and Inverse Variations

Suppose y varies directly as x, and y = 9 when x = 3/2. Find y when x = -1/2.

What is the value of y?

State what type of variation the equation represents.

• Direct

• Inverse

• Joint

• None

Is the given table a direct variation? If so, what is the constant of variation?

• Yes; 1/3

• Yes; 3

• Yes; 5

• No

a varies inversely as the square of b. If a is 1 when b is 3, find a when b is 5. 

• 0.36

• 9

• 25

• 36

Is the given table a direct or inverse variation? What is the constant of variation?

• Direct, 12

• Inverse, 12

• Direct, 1/12

• Inverse, 1/12

Which of the given graphs is a direct variation?

• A

• B

• C

• D

y varies directly with the square of x.  If y=40 when x=4, find y when x = 7

• 17.5

• 70

• 122.5

Which of the following is NOT a direct variation?

• y = -2x

• y = 1/2x

• 2x + 3y = 2

• 3y = 4x

Is this a direct variation?
y=2x

• yes

• no

Is this a direct variation?

• yes

• no