Ответ:

Пошаговое объяснение:

(b²+9)/(3b²-b³) +((b+3)/(b-3))²·(1/(b-3) +6/(9-b²) -3/(b²+3b))=3/b²

1) (b²+9)/(3b²-b³)=(b²+9)/(-b²(b-3))

2) ((b+3)/(b-3))²=(b+3)²/(b-3)²

3) 1/(b-3) +6/(9-b²) -3/(b²+3b)=1/(b-3) -6/((b-3)(b+3)) -3/(b(b+3))=(b²+3b-6b-3b+9)/(b(b-3)(b+3))=(b²-6b+9)/(b(b-3)(b+3))=(b-3)²/(b(b-3)(b+3))=(b-3)/(b(b+3))

4) (b+3)²/(b-3)² ·(b-3)/(b(b+3))=(b+3)/(b(b-3))

5) (b²+9)/(-b²(b-3)) +(b+3)/(b(b-3))=(-b²-9+b²+3b)/(b²(b-3))=(3(b-3))/(b²(b-3))=3/b²