1. **Problem:** Solve the system of equations:
$$x + 4y = 5$$
$$3x + 5y = 1$$
2. **Formula and rules:** To solve a system of linear equations, we can use substitution or elimination. Here, we use elimination.
3. **Step 1:** Multiply the first equation by 3 to align coefficients of $x$:
$$3(x + 4y) = 3(5) \Rightarrow 3x + 12y = 15$$
4. **Step 2:** Subtract the second equation from this new equation:
$$ (3x + 12y) - (3x + 5y) = 15 - 1 $$
$$ 3x - 3x + 12y - 5y = 14 $$
$$ 7y = 14 $$
5. **Step 3:** Solve for $y$:
$$ y = \frac{14}{7} = 2 $$
6. **Step 4:** Substitute $y=2$ into the first equation:
$$ x + 4(2) = 5 $$
$$ x + 8 = 5 $$
$$ x = 5 - 8 = -3 $$
7. **Answer:** The solution to the system is:
$$ x = -3, \quad y = 2 $$
Solve Linear System Ec4309
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