Math Problem Statement

(-3,-1)(-2,-3)(-4,5)(-1,-1)(0,5) find the equation of this quadratic function

Solution

To find the equation of a quadratic function that passes through the points (3,1)(-3,-1), (2,3)(-2,-3), (4,5)(-4,5), (1,1)(-1,-1), and (0,5)(0,5), we can start by assuming the general form of a quadratic function:

f(x)=ax2+bx+cf(x) = ax^2 + bx + c

We will use three points to find the coefficients aa, bb, and cc, as a quadratic equation is determined by three points. Let's select three points: (3,1)(-3, -1), (2,3)(-2, -3), and (4,5)(-4, 5). Then we will substitute the coordinates into the equation f(x)=ax2+bx+cf(x) = ax^2 + bx + c to form a system of equations.

Step 1: Write down the equations

Using the point (3,1)(-3, -1): a(3)2+b(3)+c=19a3b+c=1a(-3)^2 + b(-3) + c = -1 \quad \Rightarrow \quad 9a - 3b + c = -1

Using the point (2,3)(-2, -3): a(2)2+b(2)+c=34a2b+c=3a(-2)^2 + b(-2) + c = -3 \quad \Rightarrow \quad 4a - 2b + c = -3

Using the point (4,5)(-4, 5): a(4)2+b(4)+c=516a4b+c=5a(-4)^2 + b(-4) + c = 5 \quad \Rightarrow \quad 16a - 4b + c = 5

Step 2: Solve the system of equations

We now have the system of equations:

  1. 9a3b+c=19a - 3b + c = -1
  2. 4a2b+c=34a - 2b + c = -3
  3. 16a4b+c=516a - 4b + c = 5

We can solve this system to find aa, bb, and cc. Let me calculate that.The solution to the system of equations gives us the values:

a=2,b=8,c=5a = 2, \quad b = 8, \quad c = 5

Thus, the equation of the quadratic function is:

f(x)=2x2+8x+5f(x) = 2x^2 + 8x + 5

This quadratic function passes through the points (3,1)(-3, -1), (2,3)(-2, -3), and (4,5)(-4, 5). You can also verify that it satisfies the other two points (1,1)(-1, -1) and (0,5)(0, 5).

Would you like a detailed verification or have any questions?

Here are some related questions:

  1. How do you verify if a point lies on a quadratic function?
  2. What methods can be used to solve systems of equations like the one we solved?
  3. How does changing aa, bb, and cc affect the graph of a quadratic function?
  4. What is the significance of the vertex in a quadratic function?
  5. How can you determine the axis of symmetry for any quadratic function?

Tip: To quickly verify if a point lies on a function, substitute the coordinates into the equation and check if both sides are equal.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Systems of Equations

Formulas

Quadratic function: f(x) = ax^2 + bx + c
Substituting points into a quadratic equation to form a system of equations

Theorems

Solving a system of linear equations
General form of a quadratic function

Suitable Grade Level

Grades 9-11