Coefficient from rational expression

Find the coefficient of $x^{12}$ in the expansion of $(3 - 15 x^{3} + 18 x^{6})^{- 1}$ .

~10 minAnswer checked instantlyMultinomial TheoremGenerating Functions

H. S. Hall & S. R. Knight, Higher Algebra (1891) · Ch. XV. Multinomial Theorem, Examples XV, No. 15

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Checked against the answer in H. S. Hall & S. R. Knight, Higher Algebra (1891).