∫Calc Practice

Integral of \( \displaystyle - 12 x + 3 \left(3 x + 1\right)^{2} - 3 \)

Problem 4.361 · medium

Find \( \displaystyle \int - 12 x + 3 \left(3 x + 1\right)^{2} - 3 \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(- 12 x + 3 \left(3 x + 1\right)^{2} - 3\right)\, dx \]
    simplifyStart with the integral of the given expression.✓ Proved
  2. \[ = \int \left(27 x^{2} + 6 x\right)\, dx \]
    algebra algebra simplifyExpand the squared binomial. Distribute the 3 into the parentheses. Combine like terms.✓ Proved
  3. \[ = \int 6 x\, dx + \int 27 x^{2}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = 9 x^{3} + 3 x^{2} \]
    antiderivativeIntegrate each term using the power rule.✓ Proved
Answer \( x^{2} \left(9 x + 3\right) + C \)

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation.

The full receipt
LineStatusChecked byDetail
1✓ Provedsympy 1.14.0line 1 is the problem as stated
2✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
answer, a second way✓ Provedsympy 1.14.0SymPy differentiated the stated antiderivative back to the integrand

Reviewers

  • gpt-oss:20b: pass
  • qwen3.6:27b-mlx: pass — The solution correctly expands, simplifies, and integrates the expression using valid single-step transformations and appropriate labels.
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-10-05 — The solution correctly expands, simplifies, and integrates the expression using valid single-step transformations and appropriate labels.
  • gpt-oss:20b: pass 2026-10-05
  • qwen3.6:27b-mlx: pass 2026-10-05 — The solution correctly expands, simplifies, and integrates the expression. Each step applies a single rule from the allowed vocabulary, and the labels are appropriate.
  • gpt-oss:20b: pass 2026-10-05

Proved: SymPy reduced the difference between the two sides to zero. Checked independently: a separate method, named above, confirmed it. Checked numerically: the two sides agree at every sampled point, which is evidence, not proof. Reviewed: a model or a person read it; that is all a sentence can have. Solution by gemma4:26b, checked 2026-10-05 with SymPy 1.14.0.