ANSWERS TO YOU TRY EXERCISES 1) (4, 2) 2) a1 2 , 9b 3) (0, 7) 4) 5) infi nite number of solutions of the form {(x, y)|3x 4y 2} 6) a 7 41 , 30 41 b This time, however, working with a number like 5 37 would be diffi cult, so we will use the elimination method a second time. Go back to the original equations, (1) and (2), and use the elimination method again but eliminate the other variable, x. Then, solve for y. Eliminate x from the original system; 5x 6y 2 (1) 9x 4y 3 (2) Rewrite the System 9(5x 6y) 9(2) 45x 54y 18 5(9x 4y) 5(3) 45x 20y 15 Add the equations. 45x 54y 18 45x 20y 15 74y 33 y 33 74 Solve for y. Check to verify that the solution is a 5 37 , 33 74 b. YOU TRY 6 Solve using the elimination method. 9x 2y 3 2x 5y 4 4.3 Exercises Do the exercises, and check your work. Mixed Exercises: Objectives 1 and 2 1) What is the fi rst step you would use to solve this system by elimination if you wanted to eliminate y? 5x y 2 3x y 6 2) What is the fi rst step you would use to solve this system by elimination if you wanted to eliminate x? 4x 3y 14 8x 11y 18 Add the equations. Multiply the fi rst equation by 2. Then add the equations. For Exercises 3 and 4, choose always, sometimes, or never. 3) A system of equations with two different lines written in the form Ax By 0 will always, sometimes, or never have (0, 0) as the solution. 4) If both variables are eliminated while solving a always system of equations using elimination, the system will always, sometimes, or never have an infi nite number of solutions. sometimes *Additional answers can be found in the Answers to Exercises appendix. 268 CHAPTER 4 Linear Equations and Inequalities in Two Variables www.mhhe.com/messersmith
messersmith_power_introductory_algebra_1e_ch4_7_10
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