Solve Exponential 28046D
1. **State the problem:** Solve the equation $$6^x = 7x + 4$$ for $x$.
2. **Understand the equation:** This is a transcendental equation where an exponential function equals a linear function.
3. **Use the table to approximate:** The table gives values of $6^x$ and $7x + 4$ for various $x$:
| $x$ | $6^x$ | $7x + 4$ |
|-----|-------|----------|
| 0 | 1 | 4 |
| 1 | 6 | 11 |
| 1.4 | 12.3 | 13.8 |
| 1.45| ? | ? |
| 1.5 | 14.7 | 14.5 |
| 2 | 36 | 18 |
4. **Check values near $x=1.45$:**
- At $x=1.4$, $6^x = 12.3$ and $7x+4=13.8$, so $6^x < 7x+4$.
- At $x=1.5$, $6^x = 14.7$ and $7x+4=14.5$, so $6^x > 7x+4$.
5. **Estimate $6^{1.45}$:**
Using linear interpolation between $x=1.4$ and $x=1.5$ for $6^x$:
$$6^{1.45} \approx 12.3 + \frac{1.45 - 1.4}{1.5 - 1.4} \times (14.7 - 12.3) = 12.3 + 0.5 \times 2.4 = 12.3 + 1.2 = 13.5$$
6. **Estimate $7(1.45) + 4$:**
$$7 \times 1.45 + 4 = 10.15 + 4 = 14.15$$
7. **Compare at $x=1.45$:**
$$6^{1.45} = 13.5 < 14.15 = 7(1.45) + 4$$
8. **Conclusion:** Since $6^x$ is less than $7x+4$ at $x=1.45$ and greater at $x=1.5$, the solution lies between $1.45$ and $1.5$.
9. **Refine estimate:** Because at $1.5$, $6^x$ is slightly greater, the solution is approximately $x \approx 1.48$.
**Final answer:** $$x \approx 1.48$$