Linear System Inequality 655641
1. **State the problem:** Solve the system of linear equations:
$$4x - 3y = 12$$
$$2x + 8y = 24$$
and solve the inequality:
$$\frac{|2x + 4|}{2} \leq 6$$
2. **Solve the system of equations:**
From the first equation, the user substituted $x=6$:
$$4(6) - 3y = 12$$
$$24 - 3y = 12$$
Subtract 24 from both sides:
$$-3y = 12 - 24$$
$$-3y = -12$$
Divide both sides by $-3$:
$$y = \frac{-12}{-3} = 4$$
3. **Check the second equation with $y=4$:**
$$2x + 8(4) = 24$$
$$2x + 32 = 24$$
Subtract 32 from both sides:
$$2x = 24 - 32$$
$$2x = -8$$
Divide both sides by 2:
$$x = -4$$
4. **Verify the solution:**
Plug $x=-4$ and $y=4$ into the first equation:
$$4(-4) - 3(4) = -16 - 12 = -28 \neq 12$$
So the initial substitution $x=6$ was incorrect for the system. Let's solve the system properly using substitution or elimination.
5. **Solve by elimination:**
Multiply the first equation by 8 and the second by 3 to align $y$ coefficients:
$$8(4x - 3y) = 8(12) \Rightarrow 32x - 24y = 96$$
$$3(2x + 8y) = 3(24) \Rightarrow 6x + 24y = 72$$
Add the two equations:
$$32x - 24y + 6x + 24y = 96 + 72$$
$$38x = 168$$
Divide both sides by 38:
$$x = \frac{168}{38} = \frac{84}{19}$$
6. **Find $y$ using $x=\frac{84}{19}$ in the first equation:**
$$4\left(\frac{84}{19}\right) - 3y = 12$$
$$\frac{336}{19} - 3y = 12$$
Subtract $\frac{336}{19}$ from both sides:
$$-3y = 12 - \frac{336}{19} = \frac{228}{19} - \frac{336}{19} = -\frac{108}{19}$$
Divide both sides by $-3$:
$$y = \frac{-\frac{108}{19}}{-3} = \frac{108}{57} = \frac{36}{19}$$
7. **Solution to the system:**
$$x = \frac{84}{19}, \quad y = \frac{36}{19}$$
8. **Solve the inequality:**
$$\frac{|2x + 4|}{2} \leq 6$$
Multiply both sides by 2:
$$|2x + 4| \leq 12$$
This means:
$$-12 \leq 2x + 4 \leq 12$$
Subtract 4 from all parts:
$$-16 \leq 2x \leq 8$$
Divide all parts by 2:
$$-8 \leq x \leq 4$$
9. **Final answers:**
- System solution: $$\boxed{x = \frac{84}{19}, y = \frac{36}{19}}$$
- Inequality solution: $$\boxed{-8 \leq x \leq 4}$$