Prove that $(a+b+c)(ab+bc+ca)\geq9abc$ for $a, b, c \geq0.$

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Prove that $(a+b+c)(ab+bc+ca)\geq9abc$ for $a, b, c \geq0.$

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By AM-GM $(a+b+c)(ab+ac+bc)\geq3\sqrt[3]{abc}\cdot3\sqrt[3]{a^2b^2c^2}=9abc$

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Also we have $(a+b+c)(ab+ac+bc)-9abc=\sum\limits_{cyc}(a^2b+a^2c-2abc)=\sum\limits_{cyc}c(a-b)^2\geq0$.