x2+x2y+3x−10y+3xy−10
= x2+x2y+3x+3xy−10y−10=x2(1+y)+3x(1+y)−10(y+1)
= (x2+3x−10)(y+1)
= (x2+3x−10)=x2−2x+5x−10
= x(x−2)+5(x−2)=(x−2)(x+5)
∴x2+x2y+3x−10y+3xy−10=(x−2)(x+5)(y+1).