1. Section 2.1 Systems of Equations (no calculator)

2. Currently two options 1.Elimination (combination). 2.Substitution

9. The sum of the digits of a two-digit number is 8. When the digits are reversed, the number is increased by 18. Find the number. Let the tens digit be x and the ones digit be y. x + y = 8 The number itself is 10x + y 10y + x = 10x + y +18 The original number is 35.

10. A passenger jet took three hours to fly 1800 miles in the direction of the jetstream (with the wind). The return trip against the jetstream (against the wind) took four hours. Find the speed of the wind. Include units in your answer. Let x = speed of jet and y = speed of wind The speed of the wind is 75 miles per hour.

11. Tickets to the football game are being sold in the main office. On the first day of sales, 50 adult tickets and 40 student tickets were sold totaling $350. On the second day of sales, 20 adult tickets and 60 student tickets were sold totaling $250. How much does an adult ticket cost? Let x = cost of adult ticket and y = cost of student ticket 50 adult tickets and 40 student tickets were sold totaling $350 20 adult tickets and 60 student tickets were sold totaling $250 An adult ticket costs $5.