Linear Inequalities Worksheets with Answer Key - Free Printable
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Step-by-step solution for: Linear Inequalities Worksheets with Answer Key
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Show Answer Key & Explanations
Step-by-step solution for: Linear Inequalities Worksheets with Answer Key
Let's solve each of the linear inequalities by graphing and shading the correct region on the coordinate plane. I'll walk through each one step-by-step.
---
1. Graph the boundary line:
- If inequality is ≤ or ≥, draw a solid line.
- If it's < or >, draw a dashed line.
2. Choose a test point (usually (0,0) if not on the line).
3. Plug into the inequality to see which side to shade.
4. Shade the appropriate region.
---
Let’s go through each problem:
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- Boundary line: $ y = -\frac{1}{3}x + 2 $
- Slope: $ -\frac{1}{3} $, y-intercept: 2
- Draw a dashed line because it's strictly less than (<)
- Test point: (0,0)
- Plug in: $ 0 < -\frac{1}{3}(0) + 2 \Rightarrow 0 < 2 $ → True
- So shade the side containing (0,0) — below the line.
✔ Shade below the dashed line
---
- Boundary line: $ y = \frac{1}{2}x - 5 $
- Slope: $ \frac{1}{2} $, y-intercept: -5
- Draw a solid line because it's ≤
- Test point: (0,0)
- $ 0 \leq \frac{1}{2}(0) - 5 \Rightarrow 0 \leq -5 $? → False
- So shade the opposite side — below the line
✔ Shade below the solid line
---
- Boundary line: $ y = \frac{1}{8}x + 2 $
- Slope: $ \frac{1}{8} $, y-intercept: 2
- Draw a solid line (≥)
- Test point: (0,0)
- $ 0 \geq \frac{1}{8}(0) + 2 \Rightarrow 0 \geq 2 $? → False
- Shade the other side — above the line
✔ Shade above the solid line
---
- Boundary line: $ y = \frac{1}{4}x - 3 $
- Slope: $ \frac{1}{4} $, y-intercept: -3
- Draw a dashed line (> )
- Test point: (0,0)
- $ 0 > \frac{1}{4}(0) - 3 \Rightarrow 0 > -3 $? → True
- So shade the side containing (0,0) — above the line
✔ Shade above the dashed line
---
We need to rewrite this in slope-intercept form ($ y \leq mx + b $).
#### Step 1: Eliminate fractions
Multiply both sides by the LCD of 6, 10, and 2 → LCM is 30:
$$
30 \left( \frac{1}{6}x + \frac{1}{10}y \right) \leq 30 \cdot \frac{1}{2}
$$
$$
5x + 3y \leq 15
$$
Now solve for $ y $:
$$
3y \leq -5x + 15
\Rightarrow y \leq -\frac{5}{3}x + 5
$$
- Boundary line: $ y = -\frac{5}{3}x + 5 $
- Slope: $ -\frac{5}{3} $, y-intercept: 5
- Draw solid line (≤)
- Test point: (0,0)
- $ 0 \leq -\frac{5}{3}(0) + 5 \Rightarrow 0 \leq 5 $? → True
- So shade below the line
✔ Shade below the solid line
---
Solve for $ y $:
$$
5x \leq -4y - 12
\Rightarrow 5x + 12 \leq -4y
\Rightarrow -4y \geq 5x + 12 \quad \text{(reverse inequality when dividing by negative)}
\Rightarrow y \leq -\frac{5}{4}x - 3
$$
Wait! Let's do that carefully:
From:
$$
5x \leq -4y - 12
\Rightarrow 5x + 12 \leq -4y
\Rightarrow -4y \geq 5x + 12 \quad \text{(reversed due to multiplying by -1)}
\Rightarrow y \leq -\frac{5}{4}x - 3
$$
Yes.
- Boundary line: $ y = -\frac{5}{4}x - 3 $
- Slope: $ -\frac{5}{4} $, y-intercept: -3
- Solid line (≤)
- Test point: (0,0)
- $ 0 \leq -\frac{5}{4}(0) - 3 \Rightarrow 0 \leq -3 $? → False
- So shade the opposite side — below the line? Wait: no!
Wait — let's check again.
We have $ y \leq -\frac{5}{4}x - 3 $
Test (0,0): Is $ 0 \leq -3 $? No → False → so (0,0) is not in solution set → shade below the line?
But wait: $ y \leq \text{negative number} $ at x=0 → y ≤ -3 → so only points with y ≤ -3 are included.
So (0,0) is above the line, and since it doesn't satisfy, we shade below the line.
✔ Shade below the solid line
---
| Problem | Inequality | Line Type | Shade |
|--------|------------|-----------|-------|
| 1 | $ y < -\frac{1}{3}x + 2 $ | Dashed | Below |
| 2 | $ y \leq \frac{1}{2}x - 5 $ | Solid | Below |
| 3 | $ y \geq \frac{1}{8}x + 2 $ | Solid | Above |
| 4 | $ y > \frac{1}{4}x - 3 $ | Dashed | Above |
| 5 | $ \frac{1}{6}x + \frac{1}{10}y \leq \frac{1}{2} $ → $ y \leq -\frac{5}{3}x + 5 $ | Solid | Below |
| 6 | $ 5x \leq -4y - 12 $ → $ y \leq -\frac{5}{4}x - 3 $ | Solid | Below |
---
For each:
1. Plot the y-intercept.
2. Use the slope to find another point.
3. Draw the line (solid or dashed).
4. Test (0,0) or pick a point not on the line.
5. Shade accordingly.
---
Would you like me to generate a visual sketch or describe how to plot each line in detail?
---
🔷 General Steps for Graphing Linear Inequalities:
1. Graph the boundary line:
- If inequality is ≤ or ≥, draw a solid line.
- If it's < or >, draw a dashed line.
2. Choose a test point (usually (0,0) if not on the line).
3. Plug into the inequality to see which side to shade.
4. Shade the appropriate region.
---
Let’s go through each problem:
---
1. $ y < -\frac{1}{3}x + 2 $
- Boundary line: $ y = -\frac{1}{3}x + 2 $
- Slope: $ -\frac{1}{3} $, y-intercept: 2
- Draw a dashed line because it's strictly less than (<)
- Test point: (0,0)
- Plug in: $ 0 < -\frac{1}{3}(0) + 2 \Rightarrow 0 < 2 $ → True
- So shade the side containing (0,0) — below the line.
✔ Shade below the dashed line
---
2. $ y \leq \frac{1}{2}x - 5 $
- Boundary line: $ y = \frac{1}{2}x - 5 $
- Slope: $ \frac{1}{2} $, y-intercept: -5
- Draw a solid line because it's ≤
- Test point: (0,0)
- $ 0 \leq \frac{1}{2}(0) - 5 \Rightarrow 0 \leq -5 $? → False
- So shade the opposite side — below the line
✔ Shade below the solid line
---
3. $ y \geq \frac{1}{8}x + 2 $
- Boundary line: $ y = \frac{1}{8}x + 2 $
- Slope: $ \frac{1}{8} $, y-intercept: 2
- Draw a solid line (≥)
- Test point: (0,0)
- $ 0 \geq \frac{1}{8}(0) + 2 \Rightarrow 0 \geq 2 $? → False
- Shade the other side — above the line
✔ Shade above the solid line
---
4. $ y > \frac{1}{4}x - 3 $
- Boundary line: $ y = \frac{1}{4}x - 3 $
- Slope: $ \frac{1}{4} $, y-intercept: -3
- Draw a dashed line (> )
- Test point: (0,0)
- $ 0 > \frac{1}{4}(0) - 3 \Rightarrow 0 > -3 $? → True
- So shade the side containing (0,0) — above the line
✔ Shade above the dashed line
---
5. $ \frac{1}{6}x + \frac{1}{10}y \leq \frac{1}{2} $
We need to rewrite this in slope-intercept form ($ y \leq mx + b $).
#### Step 1: Eliminate fractions
Multiply both sides by the LCD of 6, 10, and 2 → LCM is 30:
$$
30 \left( \frac{1}{6}x + \frac{1}{10}y \right) \leq 30 \cdot \frac{1}{2}
$$
$$
5x + 3y \leq 15
$$
Now solve for $ y $:
$$
3y \leq -5x + 15
\Rightarrow y \leq -\frac{5}{3}x + 5
$$
- Boundary line: $ y = -\frac{5}{3}x + 5 $
- Slope: $ -\frac{5}{3} $, y-intercept: 5
- Draw solid line (≤)
- Test point: (0,0)
- $ 0 \leq -\frac{5}{3}(0) + 5 \Rightarrow 0 \leq 5 $? → True
- So shade below the line
✔ Shade below the solid line
---
6. $ 5x \leq -4y - 12 $
Solve for $ y $:
$$
5x \leq -4y - 12
\Rightarrow 5x + 12 \leq -4y
\Rightarrow -4y \geq 5x + 12 \quad \text{(reverse inequality when dividing by negative)}
\Rightarrow y \leq -\frac{5}{4}x - 3
$$
Wait! Let's do that carefully:
From:
$$
5x \leq -4y - 12
\Rightarrow 5x + 12 \leq -4y
\Rightarrow -4y \geq 5x + 12 \quad \text{(reversed due to multiplying by -1)}
\Rightarrow y \leq -\frac{5}{4}x - 3
$$
Yes.
- Boundary line: $ y = -\frac{5}{4}x - 3 $
- Slope: $ -\frac{5}{4} $, y-intercept: -3
- Solid line (≤)
- Test point: (0,0)
- $ 0 \leq -\frac{5}{4}(0) - 3 \Rightarrow 0 \leq -3 $? → False
- So shade the opposite side — below the line? Wait: no!
Wait — let's check again.
We have $ y \leq -\frac{5}{4}x - 3 $
Test (0,0): Is $ 0 \leq -3 $? No → False → so (0,0) is not in solution set → shade below the line?
But wait: $ y \leq \text{negative number} $ at x=0 → y ≤ -3 → so only points with y ≤ -3 are included.
So (0,0) is above the line, and since it doesn't satisfy, we shade below the line.
✔ Shade below the solid line
---
✔ Summary of All Answers:
| Problem | Inequality | Line Type | Shade |
|--------|------------|-----------|-------|
| 1 | $ y < -\frac{1}{3}x + 2 $ | Dashed | Below |
| 2 | $ y \leq \frac{1}{2}x - 5 $ | Solid | Below |
| 3 | $ y \geq \frac{1}{8}x + 2 $ | Solid | Above |
| 4 | $ y > \frac{1}{4}x - 3 $ | Dashed | Above |
| 5 | $ \frac{1}{6}x + \frac{1}{10}y \leq \frac{1}{2} $ → $ y \leq -\frac{5}{3}x + 5 $ | Solid | Below |
| 6 | $ 5x \leq -4y - 12 $ → $ y \leq -\frac{5}{4}x - 3 $ | Solid | Below |
---
📌 How to Graph Each One:
For each:
1. Plot the y-intercept.
2. Use the slope to find another point.
3. Draw the line (solid or dashed).
4. Test (0,0) or pick a point not on the line.
5. Shade accordingly.
---
Would you like me to generate a visual sketch or describe how to plot each line in detail?
Parent Tip: Review the logic above to help your child master the concept of two variable inequalities worksheet.