A.8 Direct Variation

Multiple Choice

Which of the following represents direct variation?

• y = kx

• y = k/x

• y = x/k

• y = mx + b

Multiple Choice

Which graph shows a relationship that varies directly?

Multiple Choice

Which graph shows a relationship that varies directly?

Multiple Choice

Which equation represents a relationship with direct variation?

• y = -3x

• y = 0.25x - 1

• y = 4x + 5

Multiple Choice

Which equation DOES NOT represent a relationship with direct variation?

• y = -7x

• y = 4x + 7

• y = 3.5x

​recall:

​in the equation form y = mx

​m: slope (or constant of variation)

​

​for example: y = 5x means each y value is 5 times as much as each x value

Multiple Choice

$$y=8x$$  What is the constant of variation? (aka slope)

• 8

• 8x

• cannot be determined without a graph

Multiple Choice

$$y=x$$  What is the constant of variation? (aka slope)

• -1

• cannot be determined without a graph

• 1

• 0

Multiple Choice

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

• Yes; 1/3

• Yes; 3

• Yes; 5

• No

Multiple Choice

Which of the given graphs is a direct variation?

• A

• B

• C

• D

Multiple Choice

Is this a direct variation?

• yes

• no

Multiple Choice

Direct Variation?

• yes

• no

Multiple Choice

If y vaires directly with x and y= 12 when x= 15. What is the value of x when y= 16?

• 12.8

• 20

• 11.25

• 19

Multiple Choice

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

• 26

• 3

• 58.5

• 2

Multiple Choice

 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

Multiple Choice

y varies directly with x. If y = 12 when x = 2, what is the constant of variation?

• k = 12

• k = 4

• k = 6

• k = 2

Multiple Choice

What is another name for k?

• y- intercept

• x 

• slope

• x- intercept

Multiple Choice

Is this a direct variation?
y=2x

• yes

• no

Multiple Choice

What ordered pair does a direct variation always go through when graphed?

• (0, 0)

• (1, 0)

• (0, 1)

• (1, 1)