Algebra 1 Notes SOL A.7 Plotting Points/Function Review
Mrs. Grieser
Name: ___________________________________________ Date: _______________ Block: ________
Plotting Points in the Coordinate Plane
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We use a Cartesian coordinate system to graph
values.
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We call this a coordinate plane.
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Created by French mathematician/philosopher
René Descartes,
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Extends the x-axis and y-axis into four quadrants,
labeled I, II, III, and IV, as shown to the right.
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What quadrant would point (-2, 4) lie in?__________
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Origin: The point where the x-axis and y-axis intersect
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Abscissa: Another name for the x-coordinate
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Ordinate: Another name for the y-coordinate
Naming Points
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Horizontal value (x) always named before vertical value (y): (x, y) pair
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Name points A and B in the coordinate plane at right:
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Point A is the ordered pair ________. It is in quadrant ________.
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Point B is the ordered pair ________. It is in quadrant ______.
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Find the ordered pair and quadrant for points C, D, and E.
C: _________________ D: __________________ E: _______________
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What would the ordinate (y-value) be for any point on the xaxis?__________ Points on the x-axis are called ________________
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What would the abscissa (x-value) be for any point on the yaxis? ________ Points on the y-axis are called _________________
Plotting Points
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Begin at the origin
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Move left (if negative) or right (if positive) the number of
points indicated by the abscissa (x-coordinate).
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Move up (if positive) or down (if negative) according to
the ordinate (y-coordinate).
Plot and name quadrant:
a) A (-2, 5)
b) B (3, -2)
c) C (-4, 0)
quadrant______ quadrant______ quadrant _______
Algebra 1 Notes SOL A.7 Plotting Points/Function Review
Mrs. Grieser Page 2
Relations and Functions
A function is a relation where every input is paired with one and only one (OAOO) output.
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The domain of a function or relation is the set of inputs.
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The range of a function or relation is the set of outputs.
Relation vs. Function – Which is it?
Are these relations functions? Why or why not?
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{(1,2), (3, 10), (5, 16), (-3, 5)} ___________________________________
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{(1,2), (3, 10), (5, 16), (1, 5)}
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{(1,2), (3, 2), (5, 2), (-3, 2)}
a) Mapping Diagram
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___________________________________
____________________________________
b) Ordered Pairs/Table
c) Graph
Vertical Line Test helps us determine if a graph is a function
Graphing Functions
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
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Function rules relate one variable to another.
The input variable is the independent variable
The output variable is the dependent variable, since its value is dependent on the value
of the input.
Example: The rule for a function is y = x + 2. The domain is 0, 2, 5, 7, and 8. Make a
table for the function, then identify the range. Graph the function.
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Make an x/y table (input/output table)
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Enter the domain values (or a sample of domain values)
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Run the domain values as input into the function rule
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Enter the output into corresponding y position
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Plot points
Domain = {0, 2, 5, 7, 8}
Range = __________________________________