Question

Разложи на множители многочлен x2 – 18xy – x + 9y + 81y2.
​

Answer 1

$x^{2}-18xy-x+9y+81y^{2} =(x^{2}-18xy+81y^{2})-(x-9y)=\\\\=(x-9y)^{2}-(x-9y)=\boxed{(x-9y)(x-9y-1)}$