Rational Graphs

What is the formula for Direct Variation?

• y=kx
• y=k/x
• z=ykx
• y=ky

What is the formula for joint variation?

• y=kx
• y=k/x
• z=kx
• z=kxy

Tell whether the following shows direct variation, inverse, or neither. 
y=2x

• Direct
• Inverse
• Neither

Tell whether the following shows direct variation, inverse, or neither. 
xy=9

• Direct
• Inverse
• Neither

 Y varies directly with x, and y is 84 when x is 16. Which equation represents this situation?

• y=1344x
• y=100x
• y=5.25x
• y=4/21x

Given x= 2 and y= 8; find the direct variation equation 

• y= 1/4x
• y=-4x
• y=4x
• y= -1/4x

If y varies inversely as x and x=5 when y=20, then what is the constant of variation?

• 121

• 4

• 100

• 6

The time to complete a project varies inversely with the number of employees.
If 3 people can complete the project in 7 days, how long will it take 5 people?

• 12 days
• 4.2 days
• 6.2 days
• 10 days

Tags

CCSS.7.EE.B.3

CCSS.7.EE.B.4

CCSS.7.RP.A.2

CCSS.7.RP.A.3

Suppose y varies jointly as x & z. 
If y = -180 when z = 15
and x = -3,
then find y when x = 7 and z = -5.

• -140
• 140
• -4
• 4

Suppose a varies jointly as b & c.

If a = 15 when b = 4

and c = 5,

then find b when a = 60 and c = 5.

• 320

• 225

• 16

• 3