(k+5x-36x)^2 = k^2 + 25x^2 + 1296x^2 - 10kx - 180x^2 + 180kxЗаменим k на 18:(18+5x-36x)^2 = 18^2 + 25x^2 + 1296x^2 - 1018x - 180x^2 + 18018x(18+5x-36x)^2 = 324 + 25x^2 + 1296x^2 - 180x - 180x^2 + 3240x(18+5x-36x)^2 = 1320x^2 + 3060x + 324
(k+5x-36x)^2 = k^2 + 25x^2 + 1296x^2 - 10kx - 180x^2 + 180kx
Заменим k на 18:
(18+5x-36x)^2 = 18^2 + 25x^2 + 1296x^2 - 1018x - 180x^2 + 18018x
(18+5x-36x)^2 = 324 + 25x^2 + 1296x^2 - 180x - 180x^2 + 3240x
(18+5x-36x)^2 = 1320x^2 + 3060x + 324