Math Problem Statement

Use quadratic regression to find the equation for the parabola going through these 3 points: (-13, -126), (-7, 24), and (3, -46)

Solution

To solve this problem, we need to find the equation of a quadratic function y=ax2+bx+cy = ax^2 + bx + c that passes through the given points (-13, -126), (-7, 24), and (3, -46).

Step 1: Set up a system of equations

For each point, substitute the values of xx and yy into the quadratic equation y=ax2+bx+cy = ax^2 + bx + c.

  1. For the point (-13, -126): 126=a(13)2+b(13)+c-126 = a(-13)^2 + b(-13) + c 126=169a13b+c-126 = 169a - 13b + c (Equation 1)

  2. For the point (-7, 24): 24=a(7)2+b(7)+c24 = a(-7)^2 + b(-7) + c 24=49a7b+c24 = 49a - 7b + c (Equation 2)

  3. For the point (3, -46): 46=a(3)2+b(3)+c-46 = a(3)^2 + b(3) + c 46=9a+3b+c-46 = 9a + 3b + c (Equation 3)

Step 2: Solve the system of equations

Now, we have the following system of equations:

  1. 169a13b+c=126169a - 13b + c = -126
  2. 49a7b+c=2449a - 7b + c = 24
  3. 9a+3b+c=469a + 3b + c = -46

We can solve this system using substitution, elimination, or matrix methods to find the values of aa, bb, and cc.

I'll calculate the values now.

Step 3: Solution

Let me compute the exact values of aa, bb, and cc.The solution to the system of equations gives us the values of aa, bb, and cc:

a=2,b=15,c=17a = -2, \quad b = -15, \quad c = 17

Thus, the quadratic equation for the parabola passing through the points (13,126)(-13, -126), (7,24)(-7, 24), and (3,46)(3, -46) is:

y=2x215x+17y = -2x^2 - 15x + 17

Would you like further details or have any questions?

Here are some related questions to expand on this concept:

  1. What is the process of solving a system of equations using matrices?
  2. How can quadratic regression be used for more than three points?
  3. What are the characteristics of a parabola based on the signs of aa, bb, and cc?
  4. How does one find the vertex of a quadratic equation like this?
  5. How would changing one of the points affect the resulting quadratic equation?

Tip: When solving quadratic equations, always verify your solution by plugging the values of xx and yy back into the equation to ensure consistency.

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Algebra
System of Equations
Parabolas

Formulas

Quadratic equation: y = ax^2 + bx + c
Solving systems of equations

Theorems

Quadratic Regression Theorem
Solution of systems of linear equations

Suitable Grade Level

Grades 9-12