Transcript Rectangular Coordinate System

Rectangular Coordinate System
Definitions
• X-axis – the horizontal axis
• Y –axis – the vertical axis
• Rectangular coordinate system: where the x-axis
and the y-axis intersect
• Ordered pair: identifies the location of a point on
the rectangular coordinate system
• (x coordinate, y coordinate)
• Origin: (0,0) – intersection of the x and y axis
• Quadrant: a section of the rectangular
coordinate system
How to
identify a
point?
• First locate the
origin
• Second, determine
if you are going left
or right from the
origin
– If you go left, your
x –coordinate is
negative
– If you go right,
your x –coordinate
is positive
• Third, determine
if you are going up
or down from the
origin
– If you go down,
your y –
coordinate is
negative
– If you go up, your
y –coordinate is
positive
How to graph a point?
• First Locate the origin
• Second, graph your x coordinate:
– IF the value of your x
coordinate is positive
move to the right, if
negative move to the left
• Third, graph your y coordinate:
– IF the value of your ycoordinate is positive
move up, if negative
move down
How to identify the quadrant?
• First – locate where
your point is
• Second – check your
graph on which
quadrant it is in.
Determine if an ordered pair is a
solution
• Substitute your ordered pair
into the equation:
• Check to see if the
statement is true.
• Example:
3x – y = 12
Is (0, 12) a solution?
3(0) – (12) = 12
0 – 12 = 12
No, therefore (0,12) is not a
solution
• Example: 3x – y = 12
Is (1, -9) a solution?
• Example: y = -2x
Is (-3, 8) a solution?
• Example: x = 9
Is (4, 9) a solution?
Find the missing coordinate
• First substitute the
given coordinate into
the equation.
Example:
X + 2y = 8
( ____, 9)
X + 2(9) = 8
• Simplify and solve for
the missing coordinate
X + 18 = 8
-18 -18
X = -10
Practice
1. X – 4y = 4
(____, -2)
2. 3x + y = 9
( 4, ____)
3. -2x + 7y = 14
(3, _____)
(_____, 5)
4. Y = 9
(5, ___)
(____, 9)