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Question 3046: Composition of Explicit Affine Expressions

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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← Question derivation index · Original question batch

R0005-03046 · q-20260930-r04-composition-affine-evaluation-0021

Original question and givens

Let f:R→R be f(t)=(3)t+(8) and g:R→R be g(t)=(-2)t+(-1). Find (g∘f)(8) exactly.

  • G001 — Let f:R→R be f(t)=(3)t+(8) and g:R→R be g(t)=(-2)t+(-1). Find (g∘f)(8) exactly.

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

(g∘f)(x)

After

g(f(x)):apply f first,then g

Conditions: none

The function on the right acts first;composition is not multiplication of two function values.

Step identifiers and dependencies

Rule: composition_order · Uses: G001

S002 · calculation

Before

f(x) product := mul(3, 8)

After

f(x) product = 24

Conditions: none

Substitute the current input and multiply by the coefficient.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · calculation

Before

f(x) value := sum(24, 8)

After

f(x) value = 32

Conditions: none

Then add this function's own constant term.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

g(f(x)) product := mul(-2, 32)

After

g(f(x)) product = -64

Conditions: none

Substitute the current input and multiply by the coefficient.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

g(f(x)) value := sum(-64, -1)

After

g(f(x)) value = -65

Conditions: none

Then add this function's own constant term.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

Reverse checks

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

Result

-65

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: 29b0272e3f009ad716532b7115cbeff369095f2a4c46a195aaf4b295f0d95c1e
  • candidate record SHA-256: 373f9aeb381e26c56d22931308ab5f19d30e7cfa91fa078e3ecf8d6012c83e0e
  • semantic review receipt SHA-256: 5d74de11610ebc6037a4fc9946d77154d4ed18389f8f0feeb823148b6320c4c2
  • question-first witness SHA-256: 1fba4ab0f13c2cfcc4d9fdebe492c442d43dd45700394a443daa28f333355ed9
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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