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Quadratic Equation Solver

Our Quadratic Equation Solver helps you find the roots (solutions) for any quadratic equation in the standard form ax² + bx + c = 0. Just enter the coefficients a, b, and c, and we'll show you the real or complex solutions, the discriminant, and even the vertex.

Enter the coefficient of x² (cannot be 0)

Enter the coefficient of x

Enter the constant term

How it works

Our Quadratic Equation Solver helps you find the roots (solutions) for any quadratic equation in the standard form ax² + bx + c = 0. Just enter the coefficients a, b, and c, and we'll show you the real or complex solutions, the discriminant, and even the vertex.


The Formula
The quadratic formula is given by:
x = [-b ± √(b² - 4ac)] / 2a Where:
a, b, c are coefficients
x represents the roots (solutions)

Worked Example
  1. Example: Solve x² + 5x + 6 = 0

    For the equation x² + 5x + 6 = 0, we have a=1, b=5, and c=6. Using the quadratic formula: x = [-5 ± √(5² - 4*1*6)] / (2*1) x = [-5 ± √(25 - 24)] / 2 x = [-5 ± √1] / 2 x1 = (-5 + 1) / 2 = -4 / 2 = -2 x2 = (-5 - 1) / 2 = -6 / 2 = -3 The roots are x = -2 and x = -3.


Tips, Assumptions & Limitations
  • Ensure your equation is in the standard form ax² + bx + c = 0 before entering coefficients.
  • If a coefficient is negative, include the minus sign (e.g., -5 for b).
  • If a term is missing, its coefficient is 0 (e.g., for x² + 4 = 0, b=0).
  • The discriminant (b² - 4ac) tells you about the nature of the roots: positive means two real roots, zero means one real root, negative means two complex roots.
FAQ

A quadratic equation is a polynomial equation of the second degree, meaning it contains at least one term where the variable is squared, but no higher powers. Its standard form is ax² + bx + c = 0, where 'a', 'b', and 'c' are coefficients, and 'a' cannot be zero.

The quadratic formula is a way to find the solutions (roots) of any quadratic equation. It states that for an equation ax² + bx + c = 0, the roots are given by x = [-b ± √(b² - 4ac)] / 2a.

The discriminant is the part of the quadratic formula under the square root: Δ = b² - 4ac. It tells you about the nature of the roots: if Δ > 0, there are two distinct real roots; if Δ = 0, there is one real (repeated) root; if Δ < 0, there are two complex conjugate roots.

Yes, our calculator can determine if the roots are complex (when the discriminant is negative) and will provide the complex solutions in the form 'real part ± imaginary part i'.

Companion article

Quadratic Equation Solver: Find Roots, Vertex, and Discriminant

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