Solving Quadratic Equations Graphically
Given the function f(x)=x24x6\displaystyle {f{{\left({x}\right)}}}={x}^{{2}}-{4}{x}-{6} find x when f(x)=10\displaystyle {f{{\left({x}\right)}}}=-{10} using your graphing calculator. Then follow the steps below to show the intersection graph on the computer. [Hint: Use the following window on your graphing calculator: Xmin = -5, Xmax = 7, Ymin = -15, Ymax = 5]
  1. Write the points of intersection as a list of ordered pairs below. Round the values of x\displaystyle {x} to two decimal places.
    [Hint: If two solutions exist, enter them as (x1,y1),(x2,y2)\displaystyle {\left({x}_{{1}},{y}_{{1}}\right)},{\left({x}_{{2}},{y}_{{2}}\right)}. If only one exists, enter (x1,y1)\displaystyle {\left({x}_{{1}},{y}_{{1}}\right)}. If none exist, enter DNE\displaystyle {D}{N}{E}]
  2. Use the Line Tool to draw the Horizontal Line y=10\displaystyle {y}=-{10}.
  3. Use the Polynomial Tool to draw f(x)=x24x6\displaystyle {f{{\left({x}\right)}}}={x}^{{2}}-{4}{x}-{6}. [Hint: You will need to find the vertex and one other point]
  4. Use the Point Tool to identify the points of intersection.
Write the Points of Intersections as a list of Ordered Pairs
Draw the resulting graph and plot the points of intersection
1234567-1-2-3-4-512345-1-2-3-4-5-6-7-8-9-10-11-12-13-14-15
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