A2: Unit 7 Section 5 Classwork

In a direct variation, y = 39 when x = 3. 
Find the value of y when x = 2.

• 26
• 3
• 58.5
• 2

The value of y varies directly with x.  Which function represents the relationship between x and y if y = 14 when x = 6. 

• y=20x
• y=84x
• y=7/3x
• y=3/7x

The equation 
xy =  25  represents:

• direct variation
• inverse variation
• joint variation
• none of these

• direct variation
• inverse variation
• joint variation
• none of these

• direct variation
• inverse variation
• joint variation
• none of these

If y varies jointly with the product of x and z, and y = 105 when x = 5 and z = 7, find y when x = 9 and z = 10.

• 270

• 180

• 360

• 255

If y varies jointly with the product of x and z, and y = 1000 when x = 10 and z = 20, find y when x = 8 and z = 10.

• 100

• 200

• 300

• 400

Given that y varies inversely with x, if x =7 and y = 4, what is y when x = 2?

• 14
• 10
• 2
• -14

Does the equation show an inverse variation? 
y=10/x

• yes
• no

If y varies inversely as x, and y = 23 when x = 8, find y when x = 4.

• 26

• 46

• 52

• 92