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Algebra I Recipe: Graphing a Quadratic Equation
A. Definitions
  1. Parabola – the graph of a quadratic function, which is u-shaped
  2. Vertex Point – it’s the highest or lowest point on the graph
  3. Axis of Symmetry – the vertical line that goes through the vertex point
  4. Standard Form - y = ax² + bx + c
B. Steps for Graphing a Quadratic Equation in Standard Form
  1. Determine if the graph will open up or down.
    • Opens up if "a" is positive.
      The vertex point will be the minimum point.
    • Opens down if "a" is negative.
      The vertex point is the maximum point.
  2. Find the vertex point.
    • Find the x-value by x = - b/(2a).
    • Find the y-value by substituting the x-value into the equation and solving for "y".
  3. Find more points to determine the graph.
    • Choose two integers larger than the x-value of the vertex point.
    • Choose two integers smaller than the x-value of the vertex point.
    • Substitute these values in place of "x" in the equation and solve for "y".
    • Four ordered pairs have been found
  4. Graph and connect all points that have been found.
y = 2x² - 8x + 6

y = -2x² + 8x – 5

G Redden

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