1. **Stating the problem:**
Solve the first system of equations simultaneously:
$$\begin{cases} e^{2x} - 7e^{x+1} = -10 \\ x - y = 1 \end{cases}$$
2. **Rewrite the first equation:**
Recall that $e^{2x} = (e^x)^2$ and $e^{x+1} = e^x \cdot e^1 = e \cdot e^x$.
So the first equation becomes:
$$ (e^x)^2 - 7e \cdot e^x = -10 $$
3. **Substitute:**
Let $t = e^x$, then the equation is:
$$ t^2 - 7e t = -10 $$
Rewrite as:
$$ t^2 - 7e t + 10 = 0 $$
4. **Solve quadratic in $t$:**
Using the quadratic formula:
$$ t = \frac{7e \pm \sqrt{(7e)^2 - 4 \cdot 1 \cdot 10}}{2} = \frac{7e \pm \sqrt{49e^2 - 40}}{2} $$
5. **Calculate discriminant:**
$$ \Delta = 49e^2 - 40 $$
Since $e \approx 2.718$, $49e^2$ is positive and larger than 40, so two real roots exist.
6. **Find $x$ from $t$:**
Recall $t = e^x$, so:
$$ x = \ln(t) $$
7. **Use the second equation:**
$$ x - y = 1 \implies y = x - 1 $$
8. **Summary:**
The solutions are:
$$ x = \ln\left( \frac{7e \pm \sqrt{49e^2 - 40}}{2} \right), \quad y = x - 1 $$
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**Now solve for $x$ in the second problem:**
$$ e^{x+1} \cdot e^{x-3} = 2 $$
1. **Combine exponents:**
$$ e^{x+1} \cdot e^{x-3} = e^{(x+1)+(x-3)} = e^{2x - 2} $$
2. **Set equal to 2:**
$$ e^{2x - 2} = 2 $$
3. **Take natural logarithm:**
$$ 2x - 2 = \ln(2) $$
4. **Solve for $x$:**
$$ 2x = \ln(2) + 2 $$
$$ x = \frac{\ln(2) + 2}{2} $$
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**Solve the third problem:**
$$ h x + h y = h(x - 1) + h(y - 1) $$
1. **Distribute $h$:**
$$ h x + h y = h x - h + h y - h $$
2. **Simplify:**
$$ h x + h y = h x + h y - 2h $$
3. **Subtract $h x + h y$ from both sides:**
$$ 0 = -2h $$
4. **This implies:**
$$ 2h = 0 \implies h = 0 $$
---
**Final answers:**
- For the first system:
$$ x = \ln\left( \frac{7e \pm \sqrt{49e^2 - 40}}{2} \right), \quad y = x - 1 $$
- For the second equation:
$$ x = \frac{\ln(2) + 2}{2} $$
- For the third equation:
$$ h = 0 $$
Simultaneous Exponential Dcac74
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