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Work Shown:
4x^2 - y^2
(2x)^2 - (y)^2
(2x-y)(2x+y)
When going from the second step to the third step, I used the difference of squares rule. That rule is a^2-b^2 = (a-b)(a+b). In this case, a = 2x and b = y.
Side note: (2x-y)(2x+y) is the same as (2x+y)(2x-y). We can multiply in any order.
