Independent and

Dependent Variables

Warm- Up• 4 friends went to a restaurant and

bought the same dinner that cost m amount of money. Since they had 4 people, they got $10 off. Write an expression for this situation.

• Using your expression, if the friends spent a total of $150 how much money did each meal cost?

Worksheet Answers1. m – 5 = 15

1. m = 20

2. 4s = 241. s = 6

3. 3c -20 = 551. c = 25

4. 25h + 10 = 851. h = 3

5. 3s + 8 = 4131. s = 135

6. h + 6 = 101. h = 4

7. 4d – 10 = 1501. d = 40

What are independent and

dependent variables?• Independent Variable: A variable that stands

alone and isn't changed by the other variables you are trying to measure. For example, someone's age might be an independent variable.

• Dependent Variable: A variable that depends on other factors. For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before you took the test, or even how hungry you were when you took it.

How does this relate to variables?

The independent variable is

represented by the x-value.

Independent variables

should be plotted on the x-

axis. The dependent variable is represented by the y-value. Independent variables should be plotted on the y-axis.

How do you tell them apart?

• Ask yourself the question: Which one of these depends on the other?

• http://www.ixl.com/math/algebra-1/identify-independent-and-dependent-variables

Warm-Up1. Convert 2/9 to a decimal. (top dog goes in

the house)

2. Convert .75 to a percent

3. Convert 68% to a decimal

BrainPop!!!• http://www.brainpop.com/math/algebra

/graphinglinearequations/

• In a linear equation, the graph of the coordinate pairs created from the table will make a straight line.

• We are going to create linear equations from tables and then graph!

Table Example!Carrot Cake Recipe

Cups of Flour (x) 2 3 4 5 6Number of Eggs (y)

4 6 8 10 12

1. Look for a pattern that relates each pair of values in the table.1. The first ratio is 2 cups of flour/4 eggs2. Pattern: Multiply each x value by 2

2. Write a rule1. The number of eggs (y) equals 2 times the number of

cups of flour (x).2. The rule is: y = 2 x or y = 2x

Now create a graph from the table!

• Remember: independent variable goes on the x axis and the dependent variable will go on the y-axis

• Label each axis, title the graph, and use a straight edge to connect your points!!

• Once you connect your points, they should make a straight/diagonal line.

Graph the Linear Equation y = 2x

More tables!Distance Ran

Miles 1 2 3 4Minutes 7 14 21 28

1.What is the rule for the distance he ran?

2.If he ran for 26.2 miles, how many minutes would it take?

y = 7x

y = 183.4 minutes (approx. 3 hours)

Graph the Linear Equation y = 7x

Graphing Equations Game

• http://www.ixl.com/math/grade-6/graph-linear-functions

How do independent and dependent variable work?

• http://www.mathplayground.com/functionmachine.html

• Sometimes the independent variable is called the “input” and the dependent variable is called the “output.”