x^2-9ax+20a^2 = x^2-5ax-4ax+20a^2 = (x^2-5ax)-(4ax-20a^2) = x*(x-5a)-4a*(x-5a) = (x-5a)*(x-4a)
Ответ: (x-5a)*(x-4a)
x^2-9ax+20a^2 = x^2-5ax-4ax+20a^2 = (x^2-5ax)-(4ax-20a^2) = x*(x-5a)-4a*(x-5a) = (x-5a)*(x-4a)
Ответ: (x-5a)*(x-4a)