Answer:
18
Step-by-step explanation:
hope this helps you out
V=A*L
V=72*6
V=432 in cube
9x^4 -x
( -8x + 3x^4 ) - ( -7x - 6x^4 )
Distribute the minus sign
( -8x + 3x^4 ) +7x + 6x^4
Combine like terms
3x^4 + 6x^4 -8x +7x