a) a(x-y)(x+y)
б) -(x+5)²
в) а<span>²b<span>²(a<span>²-b<span>²)</span></span></span></span>
б) -(x+5)<span>²</span>
в) прости, не знаю..
-(x^2+2xy+y^2)+ax+ay
-(x+y)^2+a(x+y)=
(x+y)(y-x+a)