Answer:
y = 3x² -15x +45
Step-by-step explanation:
Your friendly graphing calculator can tell you the coefficients of a quadratic regression function fitting these points. That function is ...
y = 3x² -15x +45
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The charting function of a spreadsheet can add a polynomial "trend line" to the chart for you. This is shown in the second attachment.
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If you want to find the quadratic coefficients by hand, you can use the given points in the equation ...
ax² +bx +c = y
to get three equations in three unknowns. The corresponding augmented matrix is ...
[tex]\left[\begin{array}{ccc|c}9&-3&1&117\\0&0&1&45\\9&3&1&27\end{array}\right][/tex]
Its solution is (a, b, c) = (3, -15, 45), in agreement with the other two solutions.
