The $x$-intercepts are the values of $x$ for which $P(x) = 0$. So, we set the polynomial equal to zero and solve for $x$:
\[\frac{1}{9} x^{4}-\frac{4}{9} x^{3} = 0\]
This simplifies to $x^4 - 4x^3 = 0$. Factoring out $x^3$, we get $x^3(x - 4) = 0$. Setting each
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