1..)(y-2)(y+3)-(y-1)² +(5-y)(y+5)

(y-2)(y+3)-(y-1)² +(5-y)(y+5)=  у^2+3y-2y-6-y^2+2y-1-y^2+25 = 3y-y^2+18 Ответ, вроде, 3y-y^2+18