Math Problem Statement

Which is the correct description description of y=4x^2-16x+12?   It has max value of -4

It has min value of -4

It has max value of 2

It has min value of 2

Solution

The equation y=4x216x+12y = 4x^2 - 16x + 12 is a quadratic function. Since the coefficient of x2x^2 is positive (4), the parabola opens upwards, which means it has a minimum value, not a maximum.

To find the minimum value, we first determine the vertex, as the vertex gives us the minimum (or maximum) point for a parabola. The x-coordinate of the vertex can be found using the formula:

xvertex=b2ax_{\text{vertex}} = \frac{-b}{2a}

For the quadratic equation y=ax2+bx+cy = ax^2 + bx + c, we have:

  • a=4a = 4
  • b=16b = -16
  • c=12c = 12

Now, calculate the x-coordinate of the vertex:

xvertex=(16)2(4)=168=2x_{\text{vertex}} = \frac{-(-16)}{2(4)} = \frac{16}{8} = 2

Next, substitute x=2x = 2 back into the equation to find the y-coordinate of the vertex (which will be the minimum value):

y=4(2)216(2)+12=4(4)32+12=1632+12=4y = 4(2)^2 - 16(2) + 12 = 4(4) - 32 + 12 = 16 - 32 + 12 = -4

Thus, the minimum value of the function is y=4y = -4.

The correct description is:

  • It has a minimum value of -4.

Would you like more details or explanations? Here are five related questions:

  1. How do you determine if a quadratic function has a minimum or maximum?
  2. How can you graph the function y=4x216x+12y = 4x^2 - 16x + 12 to verify its minimum value?
  3. What happens to the graph if the coefficient of x2x^2 changes from positive to negative?
  4. How do you complete the square to find the vertex of a quadratic equation?
  5. What are the real-life applications of quadratic functions and their minimum or maximum points?

Tip: The vertex form of a quadratic equation, y=a(xh)2+ky = a(x - h)^2 + k, makes it easy to see the vertex at (h,k)(h, k).

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Vertex of a Parabola

Formulas

x_vertex = -b / 2a
y = ax^2 + bx + c

Theorems

Vertex Theorem for Quadratic Functions

Suitable Grade Level

Grades 9-11