Concavity and Inflection Points

Let f(x)=6x2(x1)(x26)3/2(x3)3f''(x)=\frac{6x^2\left(x-1\right)}{(x^2-6)^{3/2}(x-3)^3}

Final all intervals where f(x)f(x) is concave down.
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