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Question 1161: Complete Zero Set of an Affine Function

On this page
  1. Original question and givens
  2. Definition and scope
  3. Step-by-step derivation
  4. Reverse checks
  5. Result
  6. This question review and source binding

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R0001-01161 · q-20261003-r05-linear-function-0061

Original question and givens

Over R, f(x)=(-2)x+(-2). Find its complete zero set, using R, ∅, or a set of reduced rational numbers.

  • G001 — Over R, f(x)=(-2)x+(-2). Find its complete zero set, using R, ∅, or a set of reduced rational numbers.

Definition and scope

Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.

Step-by-step derivation

S001 · implies

Before

f:R→R; f(x)=mx+b

After

m=0 gives a constant affine function

Conditions: none

An affine function allows m=0; do not impose the nondegenerate-equation condition on every affine function.

Step identifiers and dependencies

Rule: affine_domain · Uses: G001

S002 · implies

Before

-2x+(-2)=0

After

m≠0: Yes

Conditions: none

Check whether division by m is allowed; classify constant functions separately.

Step identifiers and dependencies

Rule: zero_set_case · Uses: G001, S001

S003 · calculation

Before

root := div(2, -2)

After

root = -1

Conditions: none

Move the constant and divide by nonzero m to obtain the unique candidate.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

m·root := mul(-2, -1)

After

m·root = 2

Conditions: none

Substitute into the linear term.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

f(root) := sum(2, -2)

After

f(root) = 0

Conditions: none

Verify that the function value is0.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · implies

Before

m(x₁−x₂)=0 with m≠0

After

x₁=x₂

Conditions: none

Any two zeros must coincide after subtraction and cancellation of nonzero m.

Step identifiers and dependencies

Rule: unique_affine_zero · Uses: G001, S005

Reverse checks

  • S006 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S005 · premise_and_result_audit — Recompute f(root) with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute m·root with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute root with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

{-1/1}

The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.

This question review and source binding

Review date: 2026-10-26

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.

Source hashes and review receipts
  • input commit: 0f7be61e2c22317a4075561dc822c87d881a50db
  • original question SHA-256: 32eaa5917f544a690fc9b4653805f1ad5bc3a030b5b3b72541e125747793df4c
  • candidate record SHA-256: 136e2a6b34bc68909a9d6abb22d0439899a780de7de0279754910f9fcbbdf678
  • semantic review receipt SHA-256: c3b44ce8ed60ada6902fb206627537d5f90ba2a867eaba43a36f903280c496cc
  • question-first witness SHA-256: 3e91602adc7f81a2671a2a3ffaf6a447028b56abc5853e8271673d76f30cd7ad
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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