Answer:
C, -20x^7+54x^4-10x
Explanation:
FOIL
-4x^4*5x^3=-20x^7
-4x^4*-1=4x^4
10x^5x^3=50x^4
10x*-1=-10x
-20x^7 +50x^4+4x^4-10x
Combine like terms
-20x^7+54x^4-10x
9.5m questions
12.2m answers