Direct Variation - Algebra Help

1. Wesley earns $6.50 per hour at the bookstore. The total amount of his paycheck varies directly with the number of hours he works. Write a direct variation equation for the amount of money y Wesley earns for working x hours.

2. The equation -4x + y = 0 relates the number of pages in a photo album y to the number of pictures in the album x. Tell whether the relationship is a direct variation.

3. The formula 9x - 5y = -160 relates the temperature in degrees Fahrenheit y to the temperature in degrees Celsius x. Tell whether the relationship is a direct variation.

4. The number of miles driven varies directly with the number of gallons of gas used. Erin drove 297 miles on 9 gallons of gas. How far would she be able to drive on 14 gallons of gas?

1)
y=kx, where k is a constant
y=6.50x

2)
-4x+y=0
-4x=-y
y=4x
This is a direct variation

3)
9x-5y=-160
-5y=-9x-160
y=(9/5)x + 32
This is not a direct variation

4)
y = number of miles driven
x = gallons of gas used

y=kx, where k is a contant
297 = 9k
k=33
y=33x

when x=14, y = 33(14) = 462 gallons