Answer: (a + 2)(a - 2) which is the first answer choice
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Step-by-step explanation:
Use the difference of squares factoring rule which is x^2 - y^2 = (x+y)(x-y)
In this case, x = a and y = 2
x^2 - y^2 = (x+y)(x-y)
a^2 - 2^2 = (a+2)(a-2)
a^2 - 4 = (a+2)(a-2)