Math Problem Statement

Find all complex solutions of 6x² - 4x - 1 = 0.

Solution

The equation given is:

6x24x1=06x^2 - 4x - 1 = 0

We are tasked with finding the complex solutions of this quadratic equation. To solve it, we will use the quadratic formula:

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

Here, the coefficients from the equation 6x24x1=06x^2 - 4x - 1 = 0 are:

  • a=6a = 6
  • b=4b = -4
  • c=1c = -1

Step 1: Calculate the discriminant

The discriminant Δ\Delta is given by:

Δ=b24ac\Delta = b^2 - 4ac

Substituting the values:

Δ=(4)24(6)(1)=16+24=40\Delta = (-4)^2 - 4(6)(-1) = 16 + 24 = 40

Step 2: Apply the quadratic formula

Now substitute the values of aa, bb, and Δ\Delta into the quadratic formula:

x=(4)±402(6)=4±4012x = \frac{-(-4) \pm \sqrt{40}}{2(6)} = \frac{4 \pm \sqrt{40}}{12}

Step 3: Simplify the square root

The square root of 40 can be simplified as:

40=4×10=210\sqrt{40} = \sqrt{4 \times 10} = 2\sqrt{10}

Thus, the expression for xx becomes:

x=4±21012x = \frac{4 \pm 2\sqrt{10}}{12}

Step 4: Simplify the fractions

Now simplify the fraction:

x=412±21012=13±106x = \frac{4}{12} \pm \frac{2\sqrt{10}}{12} = \frac{1}{3} \pm \frac{\sqrt{10}}{6}

Final Solutions

So, the two complex solutions for xx are:

x1=13+106,x2=13106x_1 = \frac{1}{3} + \frac{\sqrt{10}}{6}, \quad x_2 = \frac{1}{3} - \frac{\sqrt{10}}{6}

These are the solutions in terms of real numbers, but since the discriminant is positive, they are both real, not complex.

Would you like further clarification or details?

Here are five related questions:

  1. How does the discriminant affect the nature of solutions (real vs complex)?
  2. Can you always use the quadratic formula to solve any quadratic equation?
  3. What happens if the discriminant is negative?
  4. How can you solve quadratics using factoring instead of the quadratic formula?
  5. How does completing the square compare to using the quadratic formula?

Tip: Always simplify the square root and fractions when solving quadratic equations to get the cleanest form of the solution.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Complex Numbers

Formulas

Quadratic formula: x = (-b ± √(b² - 4ac)) / (2a)

Theorems

Quadratic formula

Suitable Grade Level

Grades 9-11