[4(a-b)³-3(a-b)²-5a+5b]/(a-b)
=[4(a-b)³-3(a-b)²-5(a-b)]/(a-b)
=(a-b)[4(a-b)²-3(a-b)-5]/(a-b)
=4(a-b)²-3(a-b)-5
=4a²-8ab+4b²-3a+3b-5
[4(a-b)³-3(a-b)²-5a+5b]/(a-b)
=[4(a-b)³-3(a-b)²-5(a-b)]/(a-b)
=(a-b)[4(a-b)²-3(a-b)-5]/(a-b)
=4(a-b)²-3(a-b)-5
=4a²-8ab+4b²-3a+3b-5