Work out the value of when .

Answer and explanation

Correct answer: A. 16

  1. Step 1: Square first: , so .
  2. Step 2: Then .
  3. Step 3: Add: .
Answer
16.
Why not the others: -8: This treats as , forgetting that squaring a negative gives a positive. 8: This works out as , ignoring that two negatives make a positive. 40: This squares instead of just .

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