Independent and Dependent Variables

Question

You fill up your vehicle with gas that is $3.70/gal.

 

Define Variables:    x= ___________

                             y= ___________

Equation:                _____________

 

 

Interpret the following expressions based on your equation:

a. 5x

b. y/x

c. 2y

Answer 1

The cost of gas depends on how many gallons you need to fill up your vehicle.

 

x is always the independent variable

y is always the dependent variable

 

 

x = number of gallons

y = cost of gas

 

 

One gallon of gas costs $3.70

 

y = 3.70x

 

 

a)

 

Multiply both sides of the derive formula by 5.

 

5y = 5(3.70x)

 

 

Divide both sides of the equation by 3.70

 

(5 / 3.70)y = 5x

 

 

b)

 

Divide both sides of the equation by x.

 

y / x = 3.70

 

 

This is also the slope of the linear function.

 

 

c)

 

Multiply both sides of the equation by 2.

 

2y = 2(3.70x)

 

2y = 7.40x