The answer? There is no "answer" There cannot be an answer because they are all different. In order to make calculations, the variables have to be the same. x squared, xy, y squared are the variables, and none of them match. Therefore your "answer" must look like this:
9x squared - 6xy + y squared - 81.
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78 minus78
79, -79
(2x - 9)(2x - 9) or (2x - 9)2
81 x 2 - 16 = 146
(9x)2 +9x/(45x)2 +81= 9+9x/86
9x2 - 6xy + y2 - 81 = (3x - y)2 - 92 = (3x - y - 9)(3x - y + 9)
9x2 - 6xy + y2 - 81 = (3x - y)2 - 81 = (3x - y - 9)*(3x - y + 9)
Type your answer here... 81
78 minus78
79, -79
(2x - 9)(2x - 9) or (2x - 9)2
9x^2-6xy+y^2 = (y-3x)^2 (y-3x)^2-81 -> ((y-3x)+9)((y-3x)-9)
36 + 42 - 6 + 28 - 43 + 81 - 6 = 132
81 x 2 - 16 = 146
x2-81 = (x-9)(x+9)
(9 - 5u)(9 + 5u)
(9x)2 +9x/(45x)2 +81= 9+9x/86