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Factoring 9x2+12x+49x^2 + 12x + 4

Factor 9x2+12x+49x^2 + 12x + 4 by recognizing it as a perfect square trinomial.

Step 1 — Check whether the trinomial fits the pattern a2+2ab+b2a^2 + 2ab + b^2:

  • Is the first term a perfect square? Yes: 9x2=(3x)29x^2 = (3x)^2, so a=3xa = 3x.
  • Is the last term a perfect square? Yes: 4=224 = 2^2, so b=2b = 2.
  • Is the middle term 2ab2ab? Check: 23x2=12x2 \cdot 3x \cdot 2 = 12x. Yes, the middle term is 12x12x. ✓

Step 2 — Write the square of the binomial: Since the trinomial matches the pattern with a=3xa = 3x and b=2b = 2, and the middle term is positive:

9x2+12x+4=(3x)2+2(3x)(2)+22=(3x+2)29x^2 + 12x + 4 = (3x)^2 + 2(3x)(2) + 2^2 = (3x + 2)^2

Step 3 — Check by multiplying: (3x+2)2=(3x)2+2(3x)(2)+22=9x2+12x+4(3x + 2)^2 = (3x)^2 + 2(3x)(2) + 2^2 = 9x^2 + 12x + 4 ✓.

The factored form is (3x+2)2(3x + 2)^2. By recognizing the perfect square trinomial pattern, the factoring is completed in fewer steps than the general trial-and-error method for trinomials of the form ax2+bx+cax^2 + bx + c.

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Updated 2026-04-29

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