2 Definitions X-axis – the horizontal axis Y –axis – the vertical axis Rectangular coordinate system: where the x-axis and the y-axis intersectOrdered 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 axisQuadrant: a section of the rectangular coordinate system
4 How to identify a point? First locate the origin Second, determine if you are going left or right from the originIf you go left, your x –coordinate is negativeIf you go right, your x –coordinate is positive
5 Third, determine if you are going up or down from the origin If you go down, your y –coordinate is negativeIf you go up, your y –coordinate is positive
6 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 leftThird, graph your y -coordinate:IF the value of your y- coordinate is positive move up, if negative move down
7 How to identify the quadrant? First – locate where your point isSecond – check your graph on which quadrant it is in.
8 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 = 12Is (0, 12) a solution?3(0) – (12) = 120 – 12 = 12No, therefore (0,12) is not a solutionExample: 3x – y = 12Is (1, -9) a solution?Example: y = -2xIs (-3, 8) a solution?Example: x = 9Is (4, 9) a solution?
9 Find the missing coordinate First substitute the given coordinate into the equation.Example:X + 2y = 8( ____, 9)X + 2(9) = 8Simplify and solve for the missing coordinateX + 18 = 8X = -10
10 Practice X – 4y = 4 (____, -2) 3x + y = 9 ( 4, ____) -2x + 7y = 14 (3, _____)(_____, 5)Y = 9(5, ___)(____, 9)