<s>[INST] Consider the polynomial $q(x) = x^4 + 6x^3 - 26x^2 + 72x + 30$. Consider also the linear polynomial $p(x) = x + c$. For each constant $c$ that makes $p(x)$ a factor of $q(x)$, determine the value of $c$ that produces a repeated factor. A repeated factor occurs when both $p(x)$ and $q(x)$ have a common root.[/INST]