Writing Equations in 2 variables

​Writing Equations in 2 Variables

EQUATION IN TWO VARIABLES

• Represents 2 quantaties that change in relation to one another

• Independent Variable

• Dependent Variable

INDEPENDENT VARIABLE

• Variable that is controlled

• Input ( x - coordinate)

• Located on the X-axis

• Horizontal

DEPENDENT VARIABLE

• Changes depending on how the independent variable changes.

• Output ( y - coordinate)

• Located on the Y-axis

• Vertical

Multiple Choice

On a graph, which axis shows the independent variable?

• x-axis

• y-axis

• neither

• it changes

Multiple Choice

On a graph, which axis shows the dependent variable?

• x-axis

• y-axis

• neither

• it changes

Multiple Choice

Name the INDEPENDENT variable from the table below.

• words

• minutes

Multiple Choice

Name the DEPENDENT variable from the table below.

• minutes

• bubbles

Multiple Choice

Bob streams movies through a company that charges her a $5 monthly fee plus $1.50 per movie. What is the dependent variable?

• the number of movies she rents

• the company that she rents from

• the total money it costs

• There isn't one

Multiple Choice

Michael has a math test tomorrow. His score is related to the amount of studying he does in preperation. Which is the independent variables?

• the test score

• amount of studying Michael does

SOLUTION OF AN EQUATION IN 2 VARIABLES

• Ordered pair is always (x, y)

• Substitute the values

• Solve

• Determine if the Solution is TRUE or NOT TRUE

• TRUE if both sides of the Equation are the SAME

• NOT TRUE if the numbes are DIFFERENT

Multiple Choice

Tell whether the ordered pair is a solution of the equation.

y = 4x; (0,4)

• yes

• no

Multiple Choice

Tell whether the ordered pair is a solution of the equation.

y = x + 7; (1,6)

• yes

• no

Multiple Choice

Tell whether the ordered pair is a solution of the equation.

y = x - 5; (6, 11)

• yes

• no

Multiple Choice

Tell whether the ordered pair is a solution of the equation.

y = 3x - 3 ; (1, 0)

• yes

• no

Multiple Choice

Tell whether the ordered pair is a solution of the equation.

y = 6x + 1; (2, 13)

• yes

• no

Multiple Choice

Tell whether the ordered pair is a solution of the equation.

y = 2x - 3 ; (4, 5)

• yes

• no