1. **State the problem:** Solve the system of linear equations:
$$4.6t + 8.1u = 104$$
$$3.8t - 2.7u = -8$$
2. **Choose a method:** We will use the elimination method to solve for $t$ and $u$.
3. **Eliminate one variable:** Multiply the first equation by 2.7 and the second by 8.1 to align coefficients of $u$:
$$2.7(4.6t + 8.1u) = 2.7(104) \Rightarrow 12.42t + 21.87u = 280.8$$
$$8.1(3.8t - 2.7u) = 8.1(-8) \Rightarrow 30.78t - 21.87u = -64.8$$
4. **Add the two equations to eliminate $u$:**
$$12.42t + 21.87u + 30.78t - 21.87u = 280.8 - 64.8$$
$$ (12.42 + 30.78)t + \cancel{21.87u} - \cancel{21.87u} = 216$$
$$43.2t = 216$$
5. **Solve for $t$:**
$$t = \frac{216}{43.2}$$
$$t = 5$$
6. **Substitute $t=5$ into the first original equation to find $u$:**
$$4.6(5) + 8.1u = 104$$
$$23 + 8.1u = 104$$
7. **Isolate $u$:**
$$8.1u = 104 - 23$$
$$8.1u = 81$$
8. **Solve for $u$:**
$$u = \frac{81}{8.1}$$
$$u = 10$$
**Final answer:**
$$t = 5, \quad u = 10$$
Linear System Df148A
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