Quadratic Equation Calculator — Solve Quadratic Equations

Solve quadratic equations using the quadratic formula. Get step-by-step solutions for real and complex roots. Perfect for students, teachers, and math professionals.

Calculator

Enter Coefficients

For the equation: ax² + bx + c = 0

Quadratic Formula

x = (-b ± √(b² - 4ac)) / (2a)

Where: b² - 4ac is the discriminant

Solution Results

📐

Enter the coefficients above to solve the quadratic equation

💡 Real-World Use Case

Scenario: A ball is thrown upward from a height of 2 meters with an initial velocity of 10 m/s. The height h(t) after t seconds is given by h(t) = -4.9t² + 10t + 2. To find when the ball hits the ground, we solve -4.9t² + 10t + 2 = 0. Using this calculator with a = -4.9, b = 10, c = 2, we get t ≈ 2.24 seconds (the positive root, since time cannot be negative). This helps in physics problems involving projectile motion.

Frequently Asked Questions

What is a quadratic equation?

A quadratic equation is a polynomial equation of degree 2, written in the form ax² + bx + c = 0, where a, b, and c are constants and a ≠ 0. The highest power of the variable x is 2.

What is the quadratic formula?

The quadratic formula is x = (-b ± √(b² - 4ac)) / (2a), which gives the solutions to any quadratic equation ax² + bx + c = 0. The ± symbol means we get two solutions.

What is the discriminant?

The discriminant is b² - 4ac. It determines the nature of the roots: if positive, there are two real roots; if zero, there's one real root (repeated); if negative, there are two complex conjugate roots.

How many solutions does a quadratic equation have?

A quadratic equation always has exactly two solutions (roots), which may be real or complex. If the discriminant is zero, both solutions are the same (repeated root).

What are complex roots?

Complex roots occur when the discriminant is negative. They come in conjugate pairs: if a + bi is a root, then a - bi is also a root, where i is the imaginary unit (√-1).

When do quadratic equations have real roots?

Quadratic equations have real roots when the discriminant (b² - 4ac) is greater than or equal to zero. If the discriminant is exactly zero, there's one real root; if positive, there are two distinct real roots.