Math Problem Statement

What about quadratic equation?

Solution

For a quadratic equation in the standard form ax2+bx+c=0ax^2 + bx + c = 0, the x-intercepts (also known as the roots or solutions) are found using the quadratic formula:

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

The x-intercepts are the points where the graph of the quadratic equation intersects the x-axis, which means these are the values of xx for which y=0y = 0.

Here's a step-by-step process to find the x-intercepts using the quadratic formula:

  1. Identify the coefficients: From the equation ax2+bx+c=0ax^2 + bx + c = 0, identify aa, bb, and cc.

  2. Compute the discriminant: The discriminant is Δ=b24ac\Delta = b^2 - 4ac.

    • If Δ>0\Delta > 0, there are two distinct real roots (x-intercepts).
    • If Δ=0\Delta = 0, there is exactly one real root (x-intercept).
    • If Δ<0\Delta < 0, there are no real roots (the quadratic does not intersect the x-axis).
  3. Apply the quadratic formula: Plug aa, bb, and Δ\Delta into the quadratic formula:

    x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

  4. Solve for xx: Calculate the two possible values for xx (if Δ0\Delta \geq 0).

Example

Consider the quadratic equation 2x24x6=02x^2 - 4x - 6 = 0:

  1. Identify the coefficients: a=2a = 2, b=4b = -4, c=6c = -6.

  2. Compute the discriminant: Δ=(4)24(2)(6)=16+48=64\Delta = (-4)^2 - 4(2)(-6) = 16 + 48 = 64.

  3. Apply the quadratic formula:

    x=(4)±642(2)=4±84x = \frac{-(-4) \pm \sqrt{64}}{2(2)} = \frac{4 \pm 8}{4}

  4. Solve for xx:

    x1=4+84=3x_1 = \frac{4 + 8}{4} = 3 x2=484=1x_2 = \frac{4 - 8}{4} = -1

So, the x-intercepts are x=3x = 3 and x=1x = -1.

Would you like more details or have any questions?

Here are some related questions:

  1. How do you find the vertex of a quadratic function?
  2. What is the axis of symmetry of a quadratic function?
  3. How does the discriminant determine the nature of the roots of a quadratic equation?
  4. Can a quadratic equation have no x-intercepts? Why or why not?
  5. How do you complete the square to solve a quadratic equation?
  6. What is the difference between the standard form and the vertex form of a quadratic equation?
  7. How can you determine if a quadratic function opens upwards or downwards?
  8. What is the significance of the coefficients aa, bb, and cc in a quadratic equation?

Tip: Always check the discriminant before solving a quadratic equation to understand the nature of the roots you will get. This helps in predicting the number of real solutions the equation has.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations

Formulas

Quadratic formula

Theorems

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Suitable Grade Level

Grades 9-12