1. **Problem Statement:** Find values of $x$, if any, at which the functions are not continuous.
2. **Function 11:** $f(x) = 5x^4 - 3x + 7$
- This is a polynomial function.
- Polynomials are continuous everywhere on $\mathbb{R}$.
- Therefore, $f(x)$ is continuous for all real $x$.
3. **Function 12:** $f(x) = \sqrt[3]{x - 8}$
- The cube root function $\sqrt[3]{x}$ is continuous everywhere.
- Since $f(x)$ is a composition of continuous functions (cube root and linear function $x-8$), it is continuous everywhere.
4. **Conclusion:**
- For function 11, there are no values of $x$ where $f$ is not continuous.
- For function 12, there are no values of $x$ where $f$ is not continuous.
**Final answer:** Both functions are continuous for all real numbers, so no discontinuities exist.
Continuity Check 421E29
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