Example

Factoring 4x5+12x44x^5 + 12x^4

Factor 4x5+12x44x^5 + 12x^4 completely by applying the general factoring strategy.

Step 1 — Is there a GCF? Yes. The two terms 4x54x^5 and 12x412x^4 share a numerical factor of 44 and a variable factor of x4x^4 (the lowest power of xx among all terms). The GCF is 4x44x^4. Factor it out:

4x5+12x4=4x4(x+3)4x^5 + 12x^4 = 4x^4(x + 3)

Step 2 — Classify the expression inside the parentheses. The expression (x+3)(x + 3) is a binomial. Is it a sum? Yes. Is it a sum of squares or cubes? No — xx and 33 are neither perfect squares nor perfect cubes in a useful sense. No further factoring method applies.

Step 3 — Check.

  • Is the expression factored completely? Yes — aside from the monomial 4x44x^4, the remaining factor (x+3)(x + 3) is prime.
  • Verify by multiplying: 4x4x+4x43=4x5+12x44x^4 \cdot x + 4x^4 \cdot 3 = 4x^5 + 12x^4 ✓.

The completely factored form is 4x4(x+3)4x^4(x + 3). This example demonstrates a case where the GCF alone completes the factoring — after extracting 4x44x^4, the binomial that remains is a simple linear sum that cannot be factored further by any method.

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Updated 2026-04-21

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