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Do Now:. Use elimination. 1. 2. The sum of two numbers is 20. Their difference is 4. Find the numbers. Answer : 12 and 8. (11/3, 2/3). More Elimination Method. Coordinate Algebra Standard: A.REI.6. Essential Question.
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Do Now: Use elimination. • 1. • 2. The sum of two numbers is 20. Their difference is 4. Find the numbers. Answer: 12 and 8 (11/3, 2/3)
More Elimination Method Coordinate Algebra Standard: A.REI.6
Essential Question • How do I solve a system of equations using the ELIMINATION method?
Ex. 1) Use Elimination • Answer: (-1, 4)
Ex. 2) Use Elimination • Answer: (2, 1)
Bonus Example: (-1, 2, -1)
Do Now: • Solve each system using any method you choose. • 1. y = 5x x + 2y = 22 • 2. 2y – x = -5 4y – 3x = -1 (2, 10) (-9, -7)
WORD Problems EQ • How do I solve word problems using systems of equations?
Coin Word Problems • Formula: (price1)(amount1) + (price2)(amount2) + etc. = Total $$$$$ Quarter price is: 0.25 Dime price is: 0.10 Nickel price is: 0.05 Penny price is: 0.01
Ex 1) • Sam has $2.05 in quarters and dimes. He has four more quarters than dimes. How many does he have of each coin? • Answer: 3 dimes & 7 quarters
Ex 2) • A kindergarten class collected $3.50 in nickels and dimes for the American Red Cross. In all they collected 45 coins. How many of each did they collect? • Answer: 20 nickels & 25 dimes
Age Word Problems • For age word problems, you simply translate. • Remember, “less than” and “subtracted from” statements get reversed when you write their expressions. Also, “Younger than!”
Ex 3) • Suzy is 8 years younger than her sister Madeline. If the sum of their ages is 32, how old are they? • Answer: Madeline is 20 yrs. old & Suzy is 12 yrs. old
Ex. 4) • Eight more than twice Joe’s age is 9 years less than 3 times his age. How old is he? • Answer: Joe is 17 years old