Ответ:
При \(d>0\): \(\sqrt{81d^3}=9d\sqrt d\), а \(\sqrt{4d^5}=2d^2\sqrt d\).
\(9d\sqrt d-5d\sqrt d+\frac{3}{d}\cdot2d^2\sqrt d=(9-5+6)d\sqrt d=10d\sqrt d\).
Ответ: \(10d\sqrt d\).
При \(d>0\): \(\sqrt{81d^3}=9d\sqrt d\), а \(\sqrt{4d^5}=2d^2\sqrt d\).
\(9d\sqrt d-5d\sqrt d+\frac{3}{d}\cdot2d^2\sqrt d=(9-5+6)d\sqrt d=10d\sqrt d\).
Ответ: \(10d\sqrt d\).