Understanding Direct Variation and Slope

What is the equation form that describes direct variation?

• y = mx + b

• y = kx

• y = x^2

• y = ax + b

In the equation y = 2x, what is the constant of variation?

• 0

• 1

• 2

• x

How do you calculate the slope of a line given two points?

• Use the formula m = (y2 - y1) / (x2 - x1)

• Multiply the x and y coordinates

• Subtract the y-coordinates

• Add the x-coordinates

What is the slope of the line represented by the equation y = -4x?

• -4

• 4

• 0

• 1

When graphing y = -3/2x, what does the -3/2 represent?

• The constant of proportionality

• The slope

• The x-intercept

• The y-intercept

If y varies directly as x and y = 9 when x = -3, what is the value of k?

• 3

• 9

• -3

• -9

Given y = 3x, what is x when y = -45?

• -15

• -45

• 45

• 15

How do you write a direct variation equation for distance driven over time?

• d = rt

• d = r + t

• d = r - t

• d = rt^2

If a car travels 330 miles in 5.5 hours, what is its speed in miles per hour?

• 90 mph

• 60 mph

• 120 mph

• 30 mph

Kristin ran a marathon in 3.25 hours. If the distance was 26 miles, what was her average speed?

• 6 mph

• 7 mph

• 8 mph

• 9 mph