Решение во вложении:
((15х/(х-3))+(5х/(х²-6х+9))):((3х-8)/(9-х²))+(30х/(х-3))=-5х
1) (15х/(х-3))+(5х/(х²-6х+9))=((15х*(х-3)+5х)/(х-3)²=((15х²-45х+5х)/(х-3)²=
(15х²-40х)/(х-3)²=5х*(3х-8)/(х-3)²;
2) 5х*(3х-8)/(х-3)²:((3х-8)/(9-х²))=(5х*(3х-8)/(х-3)²)*((9-х²)/(3х-8))=(9-х²)*5х/(х-3)²)=
((3-х)(3+х)*5х)/(х-3)²)=-5х*(х+3)/(х-3);
3) -5х*(х+3)/(х-3)+30х/(х-3)=(-5х²-15х+30х)/(х-3)=(15х-5х²)/(х-3)=-5х(х-3)/(х-3)=
-5х
