x(x²-4)-(x³-27)= x³-4x-x³+27= 27-4x
3(b²-2b+1)+b³+8-b³-3b²-3b-1= 3b²-6b+3+8-3b²-3b-1= 10-9b
a³-3a²+3a-1-4a(a²-1)+3(a³-1)= a³-3a²+2a-1-4a³+4a+3a³-3= 6a-4
x(x²-4)-(x³-27)= x³-4x-x³+27= 27-4x
3(b²-2b+1)+b³+8-b³-3b²-3b-1= 3b²-6b+3+8-3b²-3b-1= 10-9b
a³-3a²+3a-1-4a(a²-1)+3(a³-1)= a³-3a²+2a-1-4a³+4a+3a³-3= 6a-4