Graphing Lines and Parabolas

  • The equation of a line is y = mx + b, where m is the slope and b is the y intercept.
    One method of graphing a line is to set up a table of points. Set up x values and solve for y. Plot the points on the coordinate plane. Connect the points with a ruler, naming 3 points with their coordinates. Place arrows on each end of the line to show a line is infinite in length. Label the line with the equation.

    A second method is known as the slope-intercept method. Plot the y intercept. Then plot 3 more points following the slope. For the equation y = 2X -3, first plot the point (0,-3) which is the y intercept. Since the slope of the line is 2, the rise is 2 and the run is 1. From your first point, move up 2 and over 1. Plot the point and name the coordinates. Continue with 2 more points. Label the line.

    To graph a parabola, you must also find points for the equation. Set up X values in the interval required and solve for y. Plot the points. Connect with a smooth curve. Place arrows at each end and label the parabola with the quadratic equation.