Algebra 1 · Seeing Structure in Expressions

Factor difference of squares

Factor difference of squares.

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What you’ll learn

Factor difference of squares.

Key idea

Conjugate factors use opposite constant signs so their cross terms cancel.

Opposite signs cancel cross terms; squared differences and original expanded expressions do not satisfy the requested conjugate factor form.

Worked example

Enter the exact value or ordered values in the format requested below.

Factor x²-9 using conjugate binomials. Enter product, not original expansion.

  1. The subtracted quantities are squares x² and 3²=9.
  2. (x-3)(x+3) has opposite cross terms which cancel; constant product is -9, while repeating the negative factor creates middle coefficient -6.

Answer: (x-3)(x+3)

Quick Check

Evaluate a worked attempt at factor difference of squares, identify the first invalid step, and provide the correction.

Factor x²-196: Step 1 recognizes roots x and 14. Step 2 writes (x-14)(x-14). Locate the first invalid step and repair the product.

Choose one answer

Show a hint

Recognize both square quantities and keep subtraction distinct from a squared difference.