Упростите выражение (a/b+9b/a-6) * 1/a-3b

Question

Упростите выражение (a/b+9b/a-6) * 1/a-3b

Answer 1

(a²+9ab-6ab)/ab)*b/ab-3ab/ab=
=(a²+3ab)/ab)*b/ab-3ab/ab=
=(a²b+3ab²-3ab)/ab=
=(ab(a+3b-3)/ab=
=a+3b-3