Problem

Use quadratic regression to find the equation for the parabola going through these 3 points. $(5,210),(1,14)$, and $(-3,10)$ \[ y=[?] x^{2}+\square x+ \]

Solution

Step 1 :Set up a system of three equations using the three points given and the general form of a quadratic equation, which is \(y = ax^2 + bx + c\). For point (5,210): \(25a + 5b + c = 210\). For point (1,14): \(a + b + c = 14\). For point (-3,10): \(9a - 3b + c = 10\).

Step 2 :Subtract the second equation from the first and third to get: \(24a + 4b = 196\) and \(8a - 4b = -4\).

Step 3 :Divide the first of these by 4 and the second by 4 to get: \(6a + b = 49\) and \(2a - b = -1\).

Step 4 :Add these two equations to get: \(8a = 48\). So, \(a = 6\).

Step 5 :Substitute \(a = 6\) into the equation \(6a + b = 49\) to get: \(36 + b = 49\). So, \(b = 13\).

Step 6 :Substitute \(a = 6\) and \(b = 13\) into the equation \(a + b + c = 14\) to get: \(6 + 13 + c = 14\). So, \(c = -5\).

Step 7 :Therefore, the equation of the parabola is \(y = 6x^2 + 13x - 5\).

Step 8 :\(\boxed{y = 6x^2 + 13x - 5}\) is the final answer.

From Solvely APP
Source: https://solvelyapp.com/problems/yZYjElValm/

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