Final answer:
Lucy incorrectly multiplied 36 by the components (12 and 3) instead of squaring it, which means 36 should be multiplied by itself to get 1296, not 36.
Step-by-step explanation:
The student's question asks what Lucy did wrong when she claimed that 36 squared equals 12 x 3. The correct answer is A) She multiplied instead of squaring. To square a number means to multiply that number by itself. The expression 36 squared should be calculated as 36 x 36, which equals 1296. Instead, Lucy multiplied 36 by the factors of 12 and 3, which gives the product of 36, not 1296. This is a mistake in the application of the concept of integer powers and squaring a number.