Solutions of the Quadratic Equation

Oct 13, 2025 by windailys.com 133 views

Introduction

Solving quadratic equations is a fundamental concept in mathematics, and it has numerous applications in various fields such as physics, engineering, and economics. A quadratic equation is a polynomial equation of degree two, which means the highest power of the variable is two. The general form of a quadratic equation is $ax^2 + bx + c = 0$ , where $a$ , $b$ , and $c$ are constants, and $a$ cannot be zero. In this article, we will focus on solving the quadratic equation $x^2 - 4x + 5 = 0$ .

The Quadratic Formula

The quadratic formula is a powerful tool for solving quadratic equations. It is given by:

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

where $a$ , $b$ , and $c$ are the coefficients of the quadratic equation. In our case, $a = 1$ , $b = -4$ , and $c = 5$ . Plugging these values into the quadratic formula, we get:

x = \frac{-(-4) \pm \sqrt{(-4)^2 - 4(1)(5)}}{2(1)}

x = \frac{4 \pm \sqrt{16 - 20}}{2}

x = \frac{4 \pm \sqrt{-4}}{2}

Complex Numbers

The expression $\sqrt{-4}$ is an imaginary number, which can be written as $2i$ , where $i$ is the imaginary unit, defined as the square root of $-1$ . Therefore, the quadratic formula becomes:

x = \frac{4 \pm 2i}{2}

x = 2 \pm i

Solutions of the Quadratic Equation

The solutions of the quadratic equation $x^2 - 4x + 5 = 0$ are given by:

x = 2 + i \text{ or } x = 2 - i

These solutions can be written in the form of complex numbers, where the real part is $2$ and the imaginary part is $\pm i$ .

Comparison with the Given Options

Let's compare the solutions we obtained with the given options:

A. $x = \frac{1+i}{2}$ or $x = \frac{1-i}{2}$

B. $x = 3+i$ or $x = 3-i$

C. $x = \frac{2+i}{3}$ or $x = \frac{2-i}{3}$

D. $x = 2+i$

Only option D matches our solution, which is $x = 2+i$ or $x = 2-i$ .

Conclusion

In this article, we solved the quadratic equation $x^2 - 4x + 5 = 0$ using the quadratic formula. We obtained the solutions $x = 2+i$ or $x = 2-i$ , which can be written in the form of complex numbers. We compared our solutions with the given options and found that only option D matches our solution.

Final Answer

The final answer is $x = 2+i$ or $x = 2-i$ .

Introduction

Solving quadratic equations is a fundamental concept in mathematics, and it has numerous applications in various fields such as physics, engineering, and economics. In our previous article, we solved the quadratic equation $x^2 - 4x + 5 = 0$ using the quadratic formula. In this article, we will answer some frequently asked questions (FAQs) about solving quadratic equations.

Q: What is a quadratic equation?

A: A quadratic equation is a polynomial equation of degree two, which means the highest power of the variable is two. The general form of a quadratic equation is $ax^2 + bx + c = 0$ , where $a$ , $b$ , and $c$ are constants, and $a$ cannot be zero.

Q: What is the quadratic formula?

A: The quadratic formula is a powerful tool for solving quadratic equations. It is given by:

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

where $a$ , $b$ , and $c$ are the coefficients of the quadratic equation.

Q: How do I apply the quadratic formula?

A: To apply the quadratic formula, you need to plug in the values of $a$ , $b$ , and $c$ into the formula. For example, if you have the quadratic equation $x^2 + 5x + 6 = 0$ , you would plug in $a = 1$ , $b = 5$ , and $c = 6$ into the formula.

Q: What if the discriminant is negative?

A: If the discriminant ( $b^2 - 4ac$ ) is negative, then the quadratic equation has no real solutions. In this case, the solutions will be complex numbers.

Q: How do I simplify complex solutions?

A: To simplify complex solutions, you need to use the fact that $i^2 = -1$ . For example, if you have the solution $x = 3 + 4i$ , you can simplify it by multiplying the numerator and denominator by $i$ .

Q: Can I use the quadratic formula to solve quadratic equations with complex coefficients?

A: Yes, you can use the quadratic formula to solve quadratic equations with complex coefficients. However, you need to be careful when simplifying the solutions.

Q: What if I have a quadratic equation with a variable coefficient?

A: If you have a quadratic equation with a variable coefficient, you may need to use other methods to solve it, such as factoring or using the quadratic formula with a variable.

Q: Can I use the quadratic formula to solve quadratic equations with a zero coefficient?

A: No, you cannot use the quadratic formula to solve quadratic equations with a zero coefficient. In this case, the equation is not quadratic, and you need to use other methods to solve it.

Q: How do I check my solutions?

A: To check your solutions, you need to plug them back into the original equation and verify that they satisfy the equation.

Q: What if I get multiple solutions?

A: If you get multiple solutions, you need to check each solution to see if it satisfies the original equation.

Conclusion

In this article, we answered some frequently asked questions (FAQs) about solving quadratic equations. We covered topics such as the quadratic formula, complex solutions, and variable coefficients. We hope that this article has been helpful in clarifying some of the common misconceptions and difficulties that students face when solving quadratic equations.

Final Answer

The final answer is that solving quadratic equations is a fundamental concept in mathematics, and it has numerous applications in various fields. By understanding the quadratic formula and how to apply it, you can solve quadratic equations with ease.