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Warm Up. The distance from a number to 0 on the number line is the ___________________________. Lesson 20, Graphing on a Coordinate Plane. Expressions and equations, Functions. Vocabulary. Coordinate plane : two perpendicular axes; one horizontal, one vertical X-axis : the horizontal axis
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Warm Up • The distance from a number to 0 on the number line is the ___________________________.
Lesson 20, Graphing on a Coordinate Plane Expressions and equations, Functions
Vocabulary • Coordinate plane: two perpendicular axes; one horizontal, one vertical • X-axis: the horizontal axis • Y-axis: the vertical axis • Origin: intersection of the x-axis and y-axis • Ordered pair: identifies a point on the coordinate plane • X-coordinate: indicates horizontal distance • Y-coordinate: indicates vertical distance
Coordinate Plane • The coordinate plane has four quadrants. • The first quadrant contains all positive values • The second quadrant contains negative x values and positive y values • The third quadrant contains all negative values • The fourth quadrant contains positive x values and negative y values
Example Graph the point Graph the point
Variables • Independent variable: the variable whose value can be chosen • Dependent variable: the variable whose value is determined by the value of another variable
Example For each pair of variables, identify the independent variable and dependent variable. • Number of traffic violations, cost of auto insurance • Electric bill total, kilowatts of electricity used
Equations and ordered pairs • A solution to an equation with two variables is an ordered pair that makes the equation true. • The equation has infinitely many solutions. • We can find solutions by substituting values for to find the corresponding values.
Example The federal minimum wage is about $5 per hour. The total on a minimum-wage worker’s paycheck is dependent on the number of hours worked. The paycheck total can be calculated using the equation . Find the pay for 1, 3, 5, and 8 hours of work. Graph the solution.
Correcting homework • Be kind • Write “C.B. _____________” with your name • Hold questions until the end • Make sure I get your score sheet so your assignment is not marked missing!
Homework • 1st and 2nd hour: Lesson 20 #1-30 • 3rd hour: Lesson 19 #16-30 • Test tomorrow! Don’t forget to study!