What is the value of (x + 2)2 − (x − 2)2 when x = 1?
8
Using the identity (a + b)2 − (a − b)2 = 4ab with a = x and b = 2, the expression = 8x.
At x = 1, value = 8 × 1 = 8. (Check: (1 + 2)2 − (1 − 2)2 = 9 − 1 = 8.)
Hence, the answer is 8.
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