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Math calculator

Linear Equation Calculator

Solve ax + b = rhs for x. Identity and inconsistent cases when a = 0. Inequality /linear-inequality. Absolute value /absolute-value. Not the quadratic formula. Runs locally.

Instant result
Result
—

Enter values to calculate.

Inputs—
Mode—
Formula—
Trust summary CVP VERIFIED · CVP protocol 1.0.0-proposed · Core assurance · all published modes
Input interpretation
Enter values to calculate.
Result
—
Verified scope
all published modes
Assurance
Core
Declared partition coverage
PASS · 7/7 declared partitions (solve, inequality, abs, abs-inequality, rational, rational-inequality, invalid-domain) · Matrix
Known limitations
  • Core CVP does not include live graph, viewport, or pointer interaction.
Model
x in ax + b = rhs.
Scope
Degree 1 only
Verification
Engine tested · Source checked · v1.5.0 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Core assurance · all published modes· View Manifest · CVP overview · Specification
Versions
Calculation 1.5.0 · CVP protocol 1.0.0-proposed · Evidence 2026-09-22.discrete-algebra-cvp
Verification revision
2026-09-22.discrete-algebra-cvp · 3/3 property · digest b48961b2e1e8
Legacy regression
18/18 tests · Production surface contract 6/6
Trust layers
Verification VERIFIED · Production CURRENT · Overall CVP state: VERIFIED under CVP 1.0.0-proposed
Reference
O1 model · O2 expected_values · O2 numerical_behavior
Interfaces
PASS · UI (SSR) / REST / MCP — ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
Supplemental domain review
Not performed
Named expert review
Not performed
CVP suite
9/9 golden · 3/3 CVP boundary · 6/6 invalid · 3/3 property · 5/5 cross-interface · 1/1 cross-calculator · 6/6 CVP contract · Manifest
Sources
  • ISO 80000-2:2019 Quantities and units — Mathematics
  • CRC Standard Mathematical Tables — linear equations, absolute value, and linear rational equations
Sources
Evidence
7 legacy golden · 3 legacy boundary · legacy regression suite · 9/9 oracle-backed golden · 6/6 invalid · Artifact integrity PASS
This calculator CURRENT · Public schema 1.5.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓
Semantic contract
PASS
Full verification

Manifest identity, reference classes, interfaces, suite, and production records.

Formulas

Core equations used by this calculator.

Solutionx = (rhs − b) / a
Identitya = 0 and b = rhs → every x
Inconsistenta = 0 and b ≠ rhs → no solution
iThis page is not ax² + bx + c = 0. Use /calc/math/quadratic for quadratics. Linear inequalities are /linear-inequality. |ax+b|=rhs is /absolute-value.

How to use

1

Enter a, b, and rhs

b may be 0. rhs is the right-hand side (REST also accepts c).

2

Read x or the status

success, infinite, or inconsistent.

Example calculations

Common configurations with formula and result.

ϟ

One solution

2x + 3 = 11

x = (11 − 3) / 2
4
ϟ

Identity

0x + 5 = 5

every x
infinite

Linear Equation calculator specification

Version 1.5.0 · Engine tested

Calculation status

Review policy · Evidence

Definition
A linear equation in one unknown has the form ax + b = rhs. If a ≠ 0 there is exactly one solution x = (rhs − b)/a.
What it calculates
x in ax + b = rhs.
Inputs
  • a
  • b?
  • rhs
Outputs
  • x
  • status
Formula
x = (rhs − b) / a
Assumptions
  • Degree 1 only
  • Not quadratic
Units
  • dimensionless
Boundary conditions
  • missing a or rhs → MISSING_REQUIRED_INPUT
  • unknown mode → INVALID_MODE
Example
a=2 b=3 rhs=11 → x=4
Validation cases

2 published on this page · 18/18 tests · Production surface contract 6/6 · View evidence

  • a=2 b=3 rhs=11 → x=4
  • a=0 b=5 rhs=5 → status=infinite
Sources
  • ISO 80000-2:2019 Quantities and units — Mathematics
    Supports: Linear equation ax + b = rhs and inequality notation in one unknown
  • CRC Standard Mathematical Tables — linear equations, absolute value, and linear rational equations
    Supports: x = (rhs − b)/a; |ax+b| = rhs has two roots when rhs > 0; (ax+b)/(cx+d) = rhs clears to a linear equation excluding the pole
Calculation version
1.5.0

Other calculators in this family: Absolute Value Calculator, Absolute Value Inequality Calculator, Cubic Equation Calculator, Linear Inequality Calculator, Polynomial Evaluate Calculator, Polynomial Roots Calculator, Quadratic Formula Calculator, Quadratic Inequality Calculator . Explore all Algebra & Equations.

→ Absolute Value Calculator Solve |ax + b| = rhs. Same engine as Linear Equation. Two solutions when rhs > 0; empty when rhs < 0. Not quadratic. Not a second engine. Not CAS. Runs locally. › → Absolute Value Inequality Calculator Solve |ax + b| ○ rhs for ○ in {<, ≤, >, ≥}. Same engine as Linear Equation. Inside the branches is an interval; outside is a union. Not quadratic. Not a second engine. Not CAS. Runs locally. › → Cubic Equation Calculator Cardano / trigonometric closed form for a real cubic. Same engine as Polynomial Roots. Three real roots or one real plus a conjugate pair. Not Ferrari. Not a second cubic engine. Runs locally. › → Linear Inequality Calculator Solve ax + b ○ rhs for ○ in {<, ≤, >, ≥}. Same engine as Linear Equation. Negative a flips the inequality. Not quadratic. Not a second engine. Runs locally. › → Polynomial Evaluate Calculator Horner nested multiplication for a real polynomial at a real x. Same engine as Polynomial Roots. Not factoring. Not a second engine. Not CAS. Runs locally. › → Polynomial Roots Calculator Find all roots of a real polynomial of degree 1–8. Closed form for linear, quadratic, and cubic (Cardano); Durand–Kerner otherwise. Cubic discovery /cubic-equation. Horner evaluation /polynomial-evaluate. Not the quadratic formula page. Runs locally. › → Quadratic Formula Calculator Solve ax² + bx + c = 0 with the quadratic formula. Inequality discovery /quadratic-inequality. Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser. › → Quadratic Inequality Calculator Solve ax² + bx + c ○ rhs for ○ in {<, ≤, >, ≥}. Same engine as Quadratic. Sign of a is the outside of the roots. Not cubic. Not a second engine. Not CAS. Runs locally. ›

Frequently asked questions

Key distinctions behind the calculation.

Is this the quadratic formula?

No. Quadratics are /calc/math/quadratic. This page is degree 1.

Where is the inequality?

/calc/math/linear-inequality is mode=inequality on this same engine.

Where is absolute value?

/calc/math/absolute-value is mode=abs on this same engine: |ax + b| = rhs. The inequality is /absolute-value-inequality. (ax+b)/(cx+d)=rhs is /rational-equation. The inequality is /rational-inequality.

Where does this run?

Locally in the browser by default. REST and MCP call the same linear-equation engine.