1. **Problem:** Solve the linear inequality $$\frac{2x}{3} - \frac{1}{2} < 0$$.
2. **Formula and rules:** To solve inequalities, isolate the variable on one side. Remember, multiplying or dividing by a negative number reverses the inequality sign.
3. **Work:**
$$\frac{2x}{3} - \frac{1}{2} < 0$$
Add $$\frac{1}{2}$$ to both sides:
$$\frac{2x}{3} < \frac{1}{2}$$
Multiply both sides by 3:
$$2x < \frac{3}{2}$$
Divide both sides by 2:
$$x < \frac{3}{4}$$
4. **Answer:** The solution is $$x < \frac{3}{4}$$.
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1. **Problem:** Solve the inequality $$y \geq x - 1$$.
2. **Formula and rules:** This is a linear inequality in two variables. The boundary line is $$y = x - 1$$. The solution includes points on or above this line.
3. **Answer:** The solution set is all points $$ (x,y) $$ such that $$ y \geq x - 1 $$.
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1. **Problem:** Solve the inequality $$3x_1 - 5x_2 \leq 2$$.
2. **Formula and rules:** This inequality represents a half-plane bounded by the line $$3x_1 - 5x_2 = 2$$.
3. **Answer:** The solution set is all points $$ (x_1,x_2) $$ satisfying $$3x_1 - 5x_2 \leq 2$$.
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1. **Problem:** Solve the system:
$$5x_1 + 4x_2 \leq 40$$
$$x_1 + 2x_2 \leq 14$$
2. **Formula and rules:** Each inequality defines a half-plane. The solution is the intersection of these half-planes.
3. **Answer:** The solution set is all $$ (x_1,x_2) $$ satisfying both inequalities.
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1. **Problem:** Solve the system:
$$4x + 3y > 24$$
$$x + y \leq 8$$
2. **Formula and rules:** The first inequality is strict, so the solution excludes the boundary line.
3. **Answer:** The solution set is all $$ (x,y) $$ such that $$4x + 3y > 24$$ and $$x + y \leq 8$$.
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1. **Problem:** Solve the system of linear equations by elimination:
$$7x - 3y = -14$$
$$-3x + y = 6$$
2. **Formula and rules:** Multiply the second equation to align coefficients for elimination.
3. **Work:**
Multiply second equation by 3:
$$-9x + 3y = 18$$
Add to first equation:
$$7x - 3y + (-9x + 3y) = -14 + 18$$
$$-2x = 4$$
$$x = -2$$
Substitute $$x = -2$$ into second equation:
$$-3(-2) + y = 6$$
$$6 + y = 6$$
$$y = 0$$
4. **Answer:** $$x = -2, y = 0$$.
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1. **Problem:** Solve the system:
$$4x + 5y = 3$$
$$3x + y = 5$$
2. **Work:**
Multiply second equation by 5:
$$15x + 5y = 25$$
Subtract first equation:
$$15x + 5y - (4x + 5y) = 25 - 3$$
$$11x = 22$$
$$x = 2$$
Substitute $$x=2$$ into second equation:
$$3(2) + y = 5$$
$$6 + y = 5$$
$$y = -1$$
3. **Answer:** $$x=2, y=-1$$.
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1. **Problem:** Solve the system:
$$3x + 12y = 72$$
$$x + 4y = 24$$
2. **Work:**
Multiply second equation by 3:
$$3x + 12y = 72$$
Subtract first equation:
$$3x + 12y - (3x + 12y) = 72 - 72$$
$$0=0$$ (dependent system)
3. **Answer:** Infinite solutions along the line $$x + 4y = 24$$.
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1. **Problem:** Solve the system:
$$4x + 2y = 8$$
$$2x + y = -12$$
2. **Work:**
Multiply second equation by 2:
$$4x + 2y = -24$$
Subtract first equation:
$$4x + 2y - (4x + 2y) = -24 - 8$$
$$0 = -32$$ (contradiction)
3. **Answer:** No solution; the system is inconsistent.
Linear Inequalities Systems 6Fb7Ec
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