# Math 8 Lesson Plan 43 Using Addition to solve a System of Equations class outline for students.doc ```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:
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