Question

Разложите на множители:
а) ax+ay-x^2-2xy-y^2
б) a^2-2ab+b^2-a+b
в) a^2-b^2-c^2+2bc

Answer 1

$ax+ay-x^2-2xy-y^2=a(x+y)-(x^2+2xy+y^2)=\\=a(x+y)-(x+y)^2=(x+y)(a-(x+y))=(x+y)(a-x-y)\\\\a^2-2ab+b^2-a+b=(a^2-2ab+b^2)-(a-b)=\\=(a-b)^2-(a-b)=(a-b)(a-b-1)\\\\a^2-b^2-c^2+2bc=a^2-(b^2-2bc+c^2)=a^2-(b-c)^2=\\=(a-(b-c))(a+(b-c))=(a-b+c)(a+b-c)$