Inequality with Cubics

Show that $x^{3} + 13 a^{2} x > 5 a x^{2} + 9 a^{3}$ , given that $x > a$ .

~10 minProof · checked by AIInequalitiesFactoring

H. S. Hall & S. R. Knight, Higher Algebra (1891) · Ch. XIX. Inequalities, Examples XIX.a, No. 13

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