Math Problem Statement

A quadratic graph y = ax^2 + bx + c has a minimum point at (4, -3) and passes through the point (5, 0). Find the values of a, b, and c.

Solution

We are given the quadratic function y=ax2+bx+cy = ax^2 + bx + c with the following information:

  1. The minimum point of the parabola is at (4,3)(4, -3).
  2. The parabola passes through the point (5,0)(5, 0).

Step 1: Use the vertex form of a quadratic equation.

The vertex form of a quadratic equation is given by: y=a(xh)2+ky = a(x - h)^2 + k where (h,k)(h, k) is the vertex. From the problem, we know that the vertex (minimum point) is (4,3)(4, -3), so: y=a(x4)23y = a(x - 4)^2 - 3

Step 2: Use the point (5,0)(5, 0) to find aa.

Substitute the point (5,0)(5, 0) into the equation to find aa: 0=a(54)230 = a(5 - 4)^2 - 3 0=a(1)230 = a(1)^2 - 3 0=a30 = a - 3 a=3a = 3

Step 3: Substitute a=3a = 3 into the vertex form equation.

Now that we know a=3a = 3, the equation becomes: y=3(x4)23y = 3(x - 4)^2 - 3

Step 4: Expand the equation to the standard form.

To express the equation in the form y=ax2+bx+cy = ax^2 + bx + c, expand the vertex form: y=3(x4)23y = 3(x - 4)^2 - 3 First expand (x4)2(x - 4)^2: y=3(x28x+16)3y = 3(x^2 - 8x + 16) - 3 Distribute the 3: y=3x224x+483y = 3x^2 - 24x + 48 - 3 Simplify: y=3x224x+45y = 3x^2 - 24x + 45

Step 5: Identify aa, bb, and cc.

From the equation y=3x224x+45y = 3x^2 - 24x + 45, we can see that:

  • a=3a = 3
  • b=24b = -24
  • c=45c = 45

Thus, the values of aa, bb, and cc are: a=3,b=24,c=45a = 3, \quad b = -24, \quad c = 45

Would you like a further breakdown of the steps or any additional details? Here are some related questions:

  1. How is the vertex form of a quadratic equation derived?
  2. Why is the point (4,3)(4, -3) considered the vertex?
  3. Can you explain how to convert from vertex form to standard form?
  4. What does the value of aa tell us about the shape of the parabola?
  5. Could the minimum point change if we had different values for aa, bb, and cc?

Tip: Always substitute known points into an equation to find unknown variables before expanding or simplifying.

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Vertex Form
Standard Form

Formulas

Vertex form of quadratic equation: y = a(x - h)^2 + k
Standard form of quadratic equation: y = ax^2 + bx + c

Theorems

Vertex form and conversion to standard form

Suitable Grade Level

Grades 10-12