5.3 Exercises Check It Out Help with Homework BigIdeasMath com Vocabulary and Concept Check 1. WRITING Describe how to solve a system of linear equations by elimination. 2. NUMBER SENSE When should you use multiplication to solve a system of linear equations by elimination? 3. WHICH ONE DOESN'T BELONG? Which system of equations does not belong with the other three? Explain your reasoning. 3x + 3y = 3 -2x + y=6 2x + 3y = 11 x+y=5 2x - 3y = 7 2x - 3y = -10 3x - 2y = 10 3x - y = 3 Practice and Problem Solving Use a method from Activity 1 to solve the system. 4. xty = 3 5. -x + 3y = 0 6. 3x + 2y = 3 x- y=1 x + 3y = 12 3x - 2y = -9 Solve the system of linear equations by elimination. Check your solution. 1 7. x + 3y = 5 8. x - 2y = -7 9. 4x + 3y = -5 -x- y= -3 3x + 2y = 3 -x+ 3y = -10 10. 2x + 7y = 1 11. 2x + 5y = 16 12. 3x - 2y = 4 2x - 4y = 12 3x - 5y = -1 6x - 2y = -2 13. ERROR ANALYSIS Describe and X 5x + 2y = 9 Equation 1 correct the error in solving the 3x - 2y = -1 Equation 2 system of linear equations. 2x = 10 x = 5 14. RAFFLE TICKETS You and your The solution Is (5, -8). friend are selling raffle tickets for a new laptop. You sell 14 more tickets than your friend sells. Together, you and your friend sell 58 tickets. a. Write a system of linear equations that represents this situation. b. How many tickets does each of you sell? 15. JOGGING You can jog around your block twice and the park once in 10 minutes. You can jog around your block twice and the park 3 times in 22 minutes. a. Write a system of linear equations that represents this situation. b. How long does it take you to jog around the park? Section 5.3 Solving Systems of Linear Equations by Elimination 221