The expression (2x-y)6-(2x+y)6 is a difference of squares since it is [(2x-y)3]2 - [(2x-y)3]2. Now recall the difference of squares formula: a2 - b2 = (a+b)(a-b). Here, a = (2x-y)3 and b = (2x+y)3, so we can apply the diffference of squares formula. [(2x-y)3]2...