Simplify fully.

Answer and explanation

Correct answer: B.

  1. Step 1: Recognise the algebraic identity for the difference of two squares: .
  2. Step 2: Substitute and : and .
  3. Step 3: Subtract the two squared values: .
Answer
.
Why not the others: is only the first term ; is only the second term ; arises from an incorrect cross-product term without cancelling.

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