Respuesta :

Answer:

D

Step-by-step explanation:


Answer:

20b^4 + 23b^3 + 21b^2 Answer D

Step-by-step explanation:

4b^2 X 5b^2 = 20b^4

4b^2 X -3b = -12b^3

7b X 5b^2 = 35b^3

7b X -3b = -21b^2



35b^3 + (-12b^3) = 23b^3


20b^4 + 23b^3 -21b^2