1. **State the problem:** Solve the system of linear equations:
$$4x + 8y = 20$$
$$-x + 2y = -30$$
2. **Formula and rules:** We can use the substitution or elimination method to solve this system. Here, we'll use elimination.
3. **Step 1: Multiply the second equation by 4 to align coefficients of $x$:**
$$4(-x + 2y) = 4(-30)$$
$$-4x + 8y = -120$$
4. **Step 2: Add the first equation and the new equation:**
$$4x + 8y + (-4x + 8y) = 20 + (-120)$$
$$0x + 16y = -100$$
$$16y = -100$$
5. **Step 3: Solve for $y$:**
$$y = \frac{-100}{16}$$
Show cancellation:
$$y = \frac{-\cancel{100}}{\cancel{16}} = \frac{-25}{4}$$
6. **Step 4: Substitute $y = -\frac{25}{4}$ into the second original equation:**
$$-x + 2\left(-\frac{25}{4}\right) = -30$$
$$-x - \frac{50}{4} = -30$$
$$-x - \frac{25}{2} = -30$$
7. **Step 5: Add $\frac{25}{2}$ to both sides:**
$$-x = -30 + \frac{25}{2}$$
Convert $-30$ to fraction with denominator 2:
$$-30 = \frac{-60}{2}$$
So:
$$-x = \frac{-60}{2} + \frac{25}{2} = \frac{-35}{2}$$
8. **Step 6: Multiply both sides by $-1$ to solve for $x$:**
$$x = \frac{35}{2}$$
**Final answer:**
$$x = \frac{35}{2}, \quad y = -\frac{25}{4}$$
Solve Linear System A7C2F4
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