Math Tools

Equation Solver

Solve algebraic equations with step-by-step explanations and graph visualisations.

Linear Equation Solver

Form: ax + b = c or ax + b = cx + d

Use x as the variable. Press Enter or click Solve.

🔢

Enter an equation and click Solve

Steps and graph will appear here

Quick Examples

Click to load and solve instantly

Smart Insights

📈

Discriminant tells the story

Δ > 0: two distinct real roots. Δ = 0: one repeated root (vertex touches x-axis). Δ < 0: complex roots (parabola doesn't cross x-axis).

🔀

Cramer's Rule for systems

A 2×2 system has a unique solution when the determinant D ≠ 0. If D = 0, the equations are either parallel (no solution) or identical (infinite).

💡

Quadratic formula

x = (−b ± √(b²−4ac)) / 2a. Works for all quadratics. When the discriminant is negative, add ±i to denote complex roots.

What to do next

Who Needs an Equation Solver

  • School and college students preparing for board exams, JEE, NEET, or CAT where algebraic equation solving is tested under time pressure.
  • Teachers and tutors who need to quickly generate verified worked examples for classroom use or assignment answer keys.
  • Engineers and scientists translating physical laws into mathematical equations and needing fast, verified roots.
  • Economics and finance students modelling supply-demand equilibrium, break-even points, and optimisation problems — all of which reduce to algebraic equations.
  • Programmers and algorithm designers verifying polynomial roots during numerical method development or collision detection logic.
  • Self-learners revisiting algebra who want step-by-step transparency to understand the method, not just the answer.

Where Each Equation Type Appears in Real Life

  • Linear equations: Appear in budgeting (total cost = fixed cost + variable cost × quantity), distance-speed-time problems, salary calculations with variable pay, and any scenario where one unknown scales proportionally.
  • Quadratic equations: Govern projectile motion (height over time), profit optimisation (revenue minus cost as a function of price), lens focal length in optics, and AC circuit impedance calculations in electronics.
  • Simultaneous equations: Used to find equilibrium prices where supply equals demand, to solve mixture problems (combining solutions of different concentrations), and in network flow analysis where multiple unknowns interact.

Common Mistakes When Setting Up Equations

  • Forgetting to move all terms to one side before identifying coefficients — if you enter a = 0 in a quadratic, the equation is actually linear and the solver will behave unexpectedly.
  • Sign errors when translating word problems — "5 less than 3x" is 3x − 5, not 5 − 3x. A wrong sign flips the solution entirely.
  • Using the wrong variable for simultaneous equations — writing both equations in terms of the same unknown without checking that your substitution is consistent causes the system to collapse.
  • Ignoring extraneous solutions — solving geometrically-constrained problems (lengths, areas) may produce negative roots that are mathematically valid but physically meaningless.
  • Assuming one real root means the problem is wrong — a repeated root (discriminant = 0) is a valid and important answer in optimisation problems, representing a minimum or maximum.

What Complex Roots Mean in Practice

When the discriminant of a quadratic is negative, the solver returns complex roots in the form a ± bi. This is not an error — it is meaningful information.

  • In physics and engineering, complex roots in characteristic equations indicate oscillatory or damped behaviour in electrical circuits, mechanical systems, and control systems.
  • In geometry, complex roots confirm that a parabola does not intersect the x-axis — the curve sits entirely above or below the axis with no real crossing point.
  • In optimisation, if your profit or cost function has only complex roots, the function has no real break-even point — which is itself a useful business insight.
  • Complex roots always appear in conjugate pairs (a + bi and a − bi), which means the original polynomial always has a real coefficient structure.

Related Tools

All equation solving runs client-side instantly — no data is sent to any server.

How it works

  1. 1

    Linear: Type an equation like '2x + 5 = 15'. The solver moves terms, simplifies, and isolates x.

  2. 2

    Quadratic: Enter coefficients a, b, c for ax² + bx + c = 0, or type the full equation.

  3. 3

    System: Enter two equations in x and y. The solver uses Cramer's Rule to find both unknowns.

Example calculation

Scenario: Quadratic: x² + 5x + 6 = 0

  • Discriminant Δ = 25 − 24 = 1 (> 0, two real roots)
  • x₁ = (−5 + 1) / 2 = −2
  • x₂ = (−5 − 1) / 2 = −3

Who benefits & use cases

  • Check your algebra homework with step-by-step breakdowns.
  • Visualise quadratic solutions on an SVG parabola graph.
  • Understand Cramer's Rule for simultaneous equations.

Frequently asked questions

What does the discriminant tell us?

Δ > 0: two distinct real roots. Δ = 0: one repeated real root (vertex touches x-axis). Δ < 0: two complex (imaginary) roots — no real x-intercepts.

Can it solve cubic or higher-degree equations?

Currently supports linear and quadratic equations, and 2-variable linear systems. Higher-degree solvers are planned for a future update.

What if my system has no solution?

If the determinant D = 0, the equations are either parallel (inconsistent, no solution) or identical (dependent, infinite solutions). The solver detects and displays both cases.