Direct Variation

 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

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

• 26
• 3
• 58.5
• 2

Is this a direct variation?
y=2x

• yes
• no

 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

 y varies directly with x, and y is 16 when x is 32. Which equation represents this situation?

• y=32x
• y=16x
• y=2x
• y=(1/2)x

Is this a direct variation?

• yes
• no

What is another name for k?

• y- intercept
• x 
• slope
• x- intercept

What does the Direct Variation Equation look like?

• Y= kx
• y = mx + b
• y = b
• y = x

If y varies directly with x, and y = -20 when x = 3, what is y when x = 15?

• 100

• -2.25

• 2.25

• -100

If y varies directly with x, and y = 8 when x = 3, what is x when y = -56?

• 21

• -21

• -149.33

• 149.33