Math Problem Statement

Consider the quadratic equation y equals 2 x squared minus 8 x plus 3.

What is the graph of this equation?

Solution

The equation y=2x28x+3y = 2x^2 - 8x + 3 represents a quadratic function. The graph of a quadratic function is always a parabola. In this case, since the coefficient of x2x^2 is positive (22), the parabola will open upward.

To describe the graph in detail, we can follow these steps:

1. Vertex of the Parabola:

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 of the parabola. For the equation y=2x28x+3y = 2x^2 - 8x + 3, we can find the vertex using the formula for the x-coordinate of the vertex: x=b2ax = \frac{-b}{2a} For the given equation, a=2a = 2 and b=8b = -8. Substituting these values: x=(8)2(2)=84=2x = \frac{-(-8)}{2(2)} = \frac{8}{4} = 2 Now substitute x=2x = 2 back into the original equation to find the corresponding y-coordinate: y=2(2)28(2)+3=2(4)16+3=816+3=5y = 2(2)^2 - 8(2) + 3 = 2(4) - 16 + 3 = 8 - 16 + 3 = -5 Thus, the vertex is (2,5)(2, -5).

2. Axis of Symmetry:

The axis of symmetry is the vertical line that passes through the vertex. Since the x-coordinate of the vertex is 2, the axis of symmetry is the line x=2x = 2.

3. Direction of the Parabola:

As mentioned earlier, since the coefficient of x2x^2 is positive (a=2a = 2), the parabola opens upward.

4. Y-Intercept:

To find the y-intercept, set x=0x = 0 and solve for yy: y=2(0)28(0)+3=3y = 2(0)^2 - 8(0) + 3 = 3 Thus, the y-intercept is (0,3)(0, 3).

5. X-Intercepts:

To find the x-intercepts, set y=0y = 0 and solve for xx: 0=2x28x+30 = 2x^2 - 8x + 3 This is a quadratic equation, and we can solve it using the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} For the equation 2x28x+3=02x^2 - 8x + 3 = 0, a=2a = 2, b=8b = -8, and c=3c = 3. Substituting these values: x=(8)±(8)24(2)(3)2(2)=8±64244=8±404=8±2104x = \frac{-(-8) \pm \sqrt{(-8)^2 - 4(2)(3)}}{2(2)} = \frac{8 \pm \sqrt{64 - 24}}{4} = \frac{8 \pm \sqrt{40}}{4} = \frac{8 \pm 2\sqrt{10}}{4} Simplifying: x=84±2104=2±102x = \frac{8}{4} \pm \frac{2\sqrt{10}}{4} = 2 \pm \frac{\sqrt{10}}{2} Thus, the x-intercepts are: x=2+102andx=2102x = 2 + \frac{\sqrt{10}}{2} \quad \text{and} \quad x = 2 - \frac{\sqrt{10}}{2}

Summary:

  • The vertex of the parabola is (2,5)(2, -5).
  • The axis of symmetry is x=2x = 2.
  • The parabola opens upward.
  • The y-intercept is (0,3)(0, 3).
  • The x-intercepts are x=2+102x = 2 + \frac{\sqrt{10}}{2} and x=2102x = 2 - \frac{\sqrt{10}}{2}.

Would you like to explore the graph visually, or do you have any specific questions about these steps?

Here are some related questions:

  1. How can we transform this quadratic equation to its vertex form?
  2. How do we identify whether a parabola opens upward or downward based on the equation?
  3. How can the discriminant help us determine the number of real roots for a quadratic equation?
  4. What are the steps to graph any quadratic function?
  5. How does the value of aa in ax2+bx+cax^2 + bx + c affect the shape of the parabola?

Tip: The vertex is always the point that represents the minimum or maximum value of the quadratic function, depending on the direction the parabola opens.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Graphing Parabolas

Formulas

Vertex formula: x = -b / 2a
Quadratic formula: x = (-b ± √(b² - 4ac)) / 2a
General quadratic equation: y = ax² + bx + c

Theorems

Properties of Quadratic Functions
Axis of Symmetry
Vertex Theorem

Suitable Grade Level

Grades 8-10