Systems Checkpoint
A free Algebra I lesson from the “Systems of Linear Equations and Inequalities” unit, with a worked example and practice problems including step-by-step solutions.
This checkpoint tests whether you can choose a systems strategy. Some systems are easiest by substitution, some by elimination, and word problems require translating two relationships first.
What you'll learn
- Solve systems by graphing, substitution, and elimination
- Recognize one, none, or infinitely many solutions
- Model contexts with two equations
Worked example
Problem. Solve y = x + 4 and x + y = 16.
- Substitute x + 4 for y in x + y = 16.
- x + x + 4 = 16, so 2x = 12 and x = 6.
- y = 6 + 4 = 10.
Answer: (6, 10)
Practice problems
1. The solution to a graphed system is the...
Choices: Intersection point · steepest line · x-axis label · larger intercept
Show solution
- Graphing Systems: First identify exactly what the question is asking: The solution to a graphed system is the...
- For a system, use substitution, elimination, or graphing to find the value pair that makes both equations true.
- Both equations are true where the lines meet.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: Intersection point
2. Solve y = x + 1 and x + y = 11. Enter x.
Show solution
- Substitution: First identify exactly what the question is asking: Solve y = x + 1 and x + y = 11. Enter x.
- Use inverse operations to isolate the unknown, and keep both sides balanced at every step.
- Substitute x + 1 for y.
- 2x + 1 = 11, so x = 5.
- Check the result by substituting or estimating: the response should match 5 and make sense in the original problem.
Answer: 5
3. For y = x + 1 and x + y = 11, enter y.
Show solution
- Substitution: First identify exactly what the question is asking: For y = x + 1 and x + y = 11, enter y.
- Use inverse operations to isolate the unknown, and keep both sides balanced at every step.
- Use x = 5.
- y = 6.
- Check the result by substituting or estimating: the response should match 6 and make sense in the original problem.
Answer: 6
4. Solve y = 3x - 2 and y = 10. Enter x.
Show solution
- Substitution: First identify exactly what the question is asking: Solve y = 3x - 2 and y = 10. Enter x.
- Use inverse operations to isolate the unknown, and keep both sides balanced at every step.
- Set 3x - 2 = 10.
- 3x = 12, so x = 4.
- Check the result by substituting or estimating: the response should match 4 and make sense in the original problem.
Answer: 4
5. Solve x + y = 13 and x - y = 3. Enter x.
Show solution
- Elimination: First identify exactly what the question is asking: Solve x + y = 13 and x - y = 3. Enter x.
- Use inverse operations to isolate the unknown, and keep both sides balanced at every step.
- Add the equations: 2x = 16.
- x = 8.
- Check the result by substituting or estimating: the response should match 8 and make sense in the original problem.
Answer: 8
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