When you separate them
[tex] \frac{15d^{3} }{ {3d}^{3} } + \frac{30d^{2} }{ {3d}^{3} } + \frac{30d }{ {3d}^{3} } = x[/tex]
Solve them separately:
[tex]5 + \frac{10}{d} + \frac{10}{ {d}^{2} } = x[/tex]
Remove the denominators:
[tex]5 + 10 {d}^{ - 1} + 10 {d}^{ - 2} = x[/tex]
Find GCF (Greatest Common Factor):
[tex]5(1 + 2 {d}^{ - 1} + 2 {d}^{ - 2} ) = x[/tex]
