(3m²+5)(-3m²+5)-m²(7m+8)(7m-8)+(7m-8)+(m+1)(-2m-1)
=25-9m^4-49m^4+64m²+7m-8-2m²-3m-1
=-58m^4+62m²+4m+16
=-58+62-4+16
=16