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Complete the table of values for the equation y = x2 − 2x − 4.

Mathematics

ScanSolve AI Answer

Answer

-1.2
3.2
Graph of y = x² − 2x − 4

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Key points of y = x² − 2x − 4
Pointxy
x-intercept−1.240
y-intercept0−4
Minimum1−5
x-intercept3.240

Step-by-step solution

3 steps
  1. Complete the table of values for the equation y=x2−2x−4y = x^2 - 2x - 4.

    We will substitute each xx value into the equation to find the corresponding yy value. Note that the value for x=0x=0 in your table is incorrect; it should be −4-4.

    For x=−2x = -2:

    y=(−2)2−2(−2)−4=4+4−4=4y = (-2)^2 - 2(-2) - 4 = 4 + 4 - 4 = 4

    For x=−1x = -1:

    y=(−1)2−2(−1)−4=1+2−4=−1y = (-1)^2 - 2(-1) - 4 = 1 + 2 - 4 = -1

    For x=0x = 0:

    y=(0)2−2(0)−4=0−0−4=−4y = (0)^2 - 2(0) - 4 = 0 - 0 - 4 = -4

    For x=1x = 1:

    y=(1)2−2(1)−4=1−2−4=−5y = (1)^2 - 2(1) - 4 = 1 - 2 - 4 = -5

    For x=2x = 2:

    y=(2)2−2(2)−4=4−4−4=−4y = (2)^2 - 2(2) - 4 = 4 - 4 - 4 = -4

    For x=3x = 3:

    y=(3)2−2(3)−4=9−6−4=−1y = (3)^2 - 2(3) - 4 = 9 - 6 - 4 = -1

    For x=4x = 4:

    y=(4)2−2(4)−4=16−8−4=4y = (4)^2 - 2(4) - 4 = 16 - 8 - 4 = 4

    The completed and corrected table of values is:

    x−2−101234y4−1−4−5−4−14\begin{array}{|c|c|c|c|c|c|c|c|} \hline x & -2 & -1 & 0 & 1 & 2 & 3 & 4 \\ \hline y & 4 & -1 & -4 & -5 & -4 & -1 & 4 \\ \hline \end{array}
  2. Draw the graph of y=x2−2x−4y = x^2 - 2x - 4.

    Plot the points from the table on a graph paper. The points are (−2,4)(-2, 4), (−1,−1)(-1, -1), (0,−4)(0, -4), (1,−5)(1, -5), (2,−4)(2, -4), (3,−1)(3, -1), and (4,4)(4, 4). Connect these points with a smooth curve to form a parabola.

  3. Use the graph to solve the equation x2−2x−4=0x^2 - 2x - 4 = 0.

    To solve x2−2x−4=0x^2 - 2x - 4 = 0 graphically, find the points where the graph of y=x2−2x−4y = x^2 - 2x - 4 intersects the x-axis (where y=0y=0).
    From the table, we observe:

    • For xx between −2-2 and −1-1, yy changes from 4 to −1-1. This means the graph crosses the x-axis somewhere in this interval.
    • For xx between 3 and 4, yy changes from −1-1 to 4. This means the graph crosses the x-axis somewhere in this interval.

    By looking at the graph you draw, estimate the xx-values where the curve crosses the x-axis.
    The approximate solutions are:

    x≈−1.2x \approx \boxed{-1.2} x≈3.2x \approx \boxed{3.2}
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