-- the greatest common factor of the 15, the 9, and the 24 is 3 .
-- the greatest common factor of the b⁴, the b⁵, and the b³ is b³.
-- the greatest common factor of the c³, the c², and the c¹, is c¹.
-- the greatest common factor of the d², the d¹, and the d³ is d¹.
-- SO, the greatest common factor of the whole thing is ( 3 b³ c d ) .
Can you factor that out of the big mess ?
Please try it.
You should get (3 b³cd) (5 bc²d - 3 b²c - 8 d²) .