Solve the system: 3x + 4y = 12 and x − y = 2

Master the NLN PAX Mathematics 1 Exam with our comprehensive study guide and quizzes. Test your knowledge with multiple choice questions tailored for the PAX Math exam, featuring detailed explanations and tips to enhance your preparation and increase your chances of success.

Multiple Choice

Solve the system: 3x + 4y = 12 and x − y = 2

Explanation:
Solving a system of linear equations by substitution: from the second equation, x equals y plus 2. Substitute that into the first equation: 3(x) + 4y = 12 becomes 3(y + 2) + 4y = 12. Simplifying gives 3y + 6 + 4y = 12, so 7y + 6 = 12, hence y = 6/7. Then x = y + 2 = 6/7 + 2 = 20/7. The pair (x, y) = (20/7, 6/7) satisfies both equations, since 3x + 4y = 12 and x − y = 2 when you plug these values in. The other given pairs fail to satisfy at least one equation, so they’re not solutions.

Solving a system of linear equations by substitution: from the second equation, x equals y plus 2. Substitute that into the first equation: 3(x) + 4y = 12 becomes 3(y + 2) + 4y = 12. Simplifying gives 3y + 6 + 4y = 12, so 7y + 6 = 12, hence y = 6/7. Then x = y + 2 = 6/7 + 2 = 20/7. The pair (x, y) = (20/7, 6/7) satisfies both equations, since 3x + 4y = 12 and x − y = 2 when you plug these values in. The other given pairs fail to satisfy at least one equation, so they’re not solutions.

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