Example

Factoring 16z272z+8116z^2 - 72z + 81

Factor the trinomial 16z272z+8116z^2 - 72z + 81 by applying the perfect square trinomials pattern.

Step 1: Check if the trinomial fits the perfect square pattern a22ab+b2a^2 - 2ab + b^2.

  • Is the first term a perfect square? Yes: 16z2=(4z)216z^2 = (4z)^2, so a=4za = 4z.
  • Is the last term a perfect square? Yes: 81=9281 = 9^2, so b=9b = 9.
  • Is the middle term 2ab-2ab? Check: 2(4z)(9)=72z-2(4z)(9) = -72z. Yes, the middle term matches.

Step 2: Write the expression as the square of a binomial. Because the middle term is negative, use the pattern (ab)2(a - b)^2: 16z272z+81=(4z9)216z^2 - 72z + 81 = (4z - 9)^2

Step 3: Check by multiplying: (4z9)2=(4z)22(4z)(9)+92=16z272z+81(4z - 9)^2 = (4z)^2 - 2(4z)(9) + 9^2 = 16z^2 - 72z + 81

The factored form is (4z9)2(4z - 9)^2.

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Updated 2026-04-29

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