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Unit Converters · Free tool

Equation Solver

Solve ax+b=0, ax²+bx+c=0, and ax³+bx²+cx+d=0 instantly. Free online solver with discriminant analysis and complex roots in a+bi form. No sign-up.

Updated June 2026

ax² + bx + c = 0

·x²+·x+= 0

Discriminant Δ = 1.00000 > 0 → two distinct real roots

x1

2

x2

1

Polynomial coefficients only. For arbitrary equations involving trig or exponentials, use a numeric solver or symbolic CAS.

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What it does

Closed-form solver for linear, quadratic, and cubic equations. Quadratic uses the discriminant + the standard formula; cubic uses Cardano with the trigonometric shortcut when there are three distinct real roots. Complex roots returned in a + bi form when needed.

For numerical roots of arbitrary equations (trig, exponentials), a CAS or Newton-Raphson tool is more appropriate.

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Paste this snippet into any page. Loads on-demand (lazy), no tracking scripts, and sized to most dashboards. Replace the height to fit your layout.

<iframe src="https://freetoolarena.com/embed/equation-solver" width="100%" height="720" frameborder="0" loading="lazy" title="Equation Solver" style="border:1px solid #e2e8f0;border-radius:12px;max-width:720px;"></iframe>
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How to use it

  1. Pick the degree (linear, quadratic, cubic).
  2. Enter the coefficients.
  3. Read each root + the discriminant case explained.

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