Mathematics (US) - 0444 CIE

Systems Of Linear Equations In Two Variables

Overview

One equation with two unknowns has endless solutions; pair it with a second equation and the answer usually pins down to a single point. Solving a system of two linear equations means finding the one pair of values that satisfies both at once, the exact spot where two lines cross.

In this lesson you will solve systems of two linear equations in two variables using elimination and substitution, the two reliable algebraic methods. You will learn to choose the easier route for each problem and to check your answer in both original equations.

Objectives

  1. Solve systems of two linear equations in two variables algebraically and (Extended) graphically.

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Lesson Note

Many real problems involve two unknowns linked by two conditions: the cost of two kinds of ticket, the speed of a boat and a current, a mix of two ingredients. A system of linear equations captures both conditions and solves them together, which is far more powerful than guessing.

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Lesson Evaluation

Congratulations on completing the lesson on Systems Of Linear Equations In Two Variables. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

  1. Solve 2x + y = 8 and x - y = 1. A. (3, 2) B. (2, 3) C. (1, 6) D. (4, 0) Answer: A
  2. Solve y = 2x - 1 and 3x + y = 9. A. (3, 2) B. (2, 3) C. (1, 1) D. (2, 5) Answer: B
  3. To eliminate y from x + y = 5 and x - y = 1, you should: A. Add the equations B. Subtract the equations C. Multiply them D. Square them Answer: A
  4. The solution of a system of two linear equations represents: A. The midpoint of two lines B. Where the two lines cross C. The gradient of a line D. The y-intercept Answer: B
  5. Solve x + y = 7 and x - y = 3. A. (5, 2) B. (2, 5) C. (4, 3) D. (3, 4) Answer: A

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