1. **State the problem:** Solve the equation $y^2 + y^3 = 14$ for $y$.
2. **Rewrite the equation:** The equation can be written as
$$y^3 + y^2 = 14$$
3. **Isolate terms:** We want to find values of $y$ that satisfy this cubic equation.
4. **Try to find rational roots:** Use the Rational Root Theorem to test possible roots among factors of 14: $\pm1, \pm2, \pm7, \pm14$.
5. **Test $y=2$:**
$$2^3 + 2^2 = 8 + 4 = 12 \neq 14$$
6. **Test $y=1$:**
$$1^3 + 1^2 = 1 + 1 = 2 \neq 14$$
7. **Test $y= -1$:**
$$(-1)^3 + (-1)^2 = -1 + 1 = 0 \neq 14$$
8. **Test $y= 7$:**
$$7^3 + 7^2 = 343 + 49 = 392 \neq 14$$
9. **Test $y= -2$:**
$$(-2)^3 + (-2)^2 = -8 + 4 = -4 \neq 14$$
10. Since no simple rational root works, use substitution or numerical methods.
11. **Rewrite as:**
$$y^3 + y^2 - 14 = 0$$
12. **Use the cubic formula or approximate numerically:**
13. **Approximate root:** By testing values between 2 and 3:
- At $y=2.5$:
$$2.5^3 + 2.5^2 = 15.625 + 6.25 = 21.875 > 14$$
- At $y=2$:
$$12 < 14$$
14. So root lies between 2 and 2.5.
15. **Try $y=2.2$:**
$$2.2^3 + 2.2^2 = 10.648 + 4.84 = 15.488 > 14$$
16. **Try $y=2.1$:**
$$2.1^3 + 2.1^2 = 9.261 + 4.41 = 13.671 < 14$$
17. Root is between 2.1 and 2.2, closer to 2.15.
18. **Final approximate solution:**
$$y \approx 2.14$$
**Answer:** The solution to $y^2 + y^3 = 14$ is approximately $y \approx 2.14$.
Solve Cubic 6A868E
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