1. Solve the inequality $\frac{2x}{3} - \frac{1}{2} < 0$.
Step 1: Add $\frac{1}{2}$ to both sides:
$$\frac{2x}{3} < \frac{1}{2}$$
Step 2: Multiply both sides by 3 to clear the denominator:
$$\cancel{3} \times \frac{2x}{\cancel{3}} < \frac{1}{2} \times 3$$
$$2x < \frac{3}{2}$$
Step 3: Divide both sides by 2:
$$\frac{\cancel{2}x}{\cancel{2}} < \frac{3}{2} \times \frac{1}{2}$$
$$x < \frac{3}{4}$$
2. Solve the inequality $y \geq x - 1$.
This is already in slope-intercept form. The solution set is all points on or above the line $y = x - 1$.
3. Solve $3x_1 - 5x_2 \leq 2$.
This inequality describes a half-plane including the line $3x_1 - 5x_2 = 2$ and all points below it.
4. Solve the system:
$$5x_1 + 4x_2 \leq 40$$
$$x_1 + 2x_2 \leq 14$$
These inequalities describe the intersection of two half-planes.
5. Solve the system:
$$4x + 3y > 24$$
$$x + y \leq 8$$
The solution set is the intersection of the half-plane above the line $4x + 3y = 24$ and below or on the line $x + y = 8$.
II. Solve systems of linear equations by elimination.
1. Solve:
$$7x - 3y = -14$$
$$-3x + y = 6$$
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:
$$-3(-2) + y = 6$$
$$6 + y = 6$$
$$y = 0$$
Solution: $(-2, 0)$
2. Solve:
$$4x + 5y = 3$$
$$3x + y = 5$$
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:
$$3(2) + y = 5$$
$$6 + y = 5$$
$$y = -1$$
Solution: $(2, -1)$
3. Solve:
$$3x + 12y = 72$$
$$x + 4y = 24$$
Multiply second equation by 3:
$$3x + 12y = 72$$
Subtract first equation:
$$(3x + 12y) - (3x + 12y) = 72 - 72$$
$$0 = 0$$
This means the two equations are dependent; infinite solutions along the line $x + 4y = 24$.
4. Solve:
$$4x + 2y = 8$$
$$2x + y = -12$$
Multiply second equation by 2:
$$4x + 2y = -24$$
Subtract first equation:
$$(4x + 2y) - (4x + 2y) = -24 - 8$$
$$0 = -32$$
Contradiction, no solution.
Desmos functions for graphing inequalities and equations:
- $y = x - 1$
- $3x_1 - 5x_2 = 2$
- $5x_1 + 4x_2 = 40$
- $x_1 + 2x_2 = 14$
- $4x + 3y = 24$
- $x + y = 8$
- $7x - 3y = -14$
- $-3x + y = 6$
- $4x + 5y = 3$
- $3x + y = 5$
- $3x + 12y = 72$
- $x + 4y = 24$
- $4x + 2y = 8$
- $2x + y = -12$
Linear Inequalities Systems 292328
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.