(9x-1)+(9*2x) = 324
9x-1+(18x) = 324
9x-1+18x = 324
27x-1 - 324
27x = 324+1
27x = 325
x = 325 в знаменатели 27 325/27
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1/ctga + cosa/1+sina = 1 / cosa/sina + cosa / 1 + sina = sina/cosa + cosa / 1 + sina = sina + sin^2a + cos^2a / (1 + sina)cosa = sina + 1 / (1 + sina)cosa = 1/cosa
(2х+у)(4х^2-4ху+у^2)+(х-2у)(х^2-2ху+4у^2)