Given that,
(6ab3−5ab)(2a2+b−5)+ab(a2+1)+ab3(3a3+2b+1)
=12a3b3+6ab4−30ab3−10a2b−5ab2−25ab+a3b+ab+3a4b3+2ab4+ab3
=12a3b3+8ab4−29ab3−10a2b−5ab2−2ab+a3b+3a4b3
=3a3b3(4+a)−5ab(2a+b)+ab3(8b−29)+ab(a2−2)
Hence, this is the answer.