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Sewanhaka High School Math 8 Per:________________ Name:________________________________ H.W. #43: Ditto DO-NOW #43: 1) Solve the following system of equations algebraically: y = 2x + 5 3x + y = 20 Mrs. Lidowsky, Principal Mr. Long, Teacher Date:_____________________ 2) What is the slope and y intercept of 3x + y = 20? 3) What are the first 4 multiples of 7? Topic: Expressions and Equations Main Idea: Solving a system of equations algebraically using addition Aim: RECALL NOTES I am thinking of two numbers whose sum is 10 and whose difference is 4. What are the numbers? Try substitution to solve the previous system. Is there an easier method to solve the previous system? Check it. Solve the system of equations by using addition or subtraction: 3x + y = 12 2x – y = 8 Solve the system of equations by using addition or subtraction: 5x + 2y = 15 4x + 2y = 12 Math 8 – LP #43 – Page 2 Solve the system of equations 4x + 2y = 14 and x + 2y = 11 algebraically using addition or subtraction. Drill: Determine which method to use, substitution or addition, to solve the following systems of equations algebraically and make sure to check: 1) x = 2y + 4 2) 2a + b = 8 3) y = 2x 4) 3x + 4y = 25 x + y = 10 a+b=2 x + y = 12 2x – 4y = 10 Summary: