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