Download Notes 11 – 4 Day 2- Elimination Using Addition

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Notes 11 – 4 Day 2- Elimination Using Addition, Subtraction and Multiplication
Algebra 1
Objective: At the end of this lesson, students should be able to:
 Solve systems of equations by the elimination method using multiplication and addition
Define elimination in your own words:
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Example 1:
Operation:
Example 2:
2a + 13c = 36
2a + 9c = 28
x – 4y = 6
3x + 4y = 10
(
(
,
)
,
Operation:
)
When solving a system of equations using Elimination, when do we need to multiply an equation
by -1?
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WHY do we need to multiply an equation by -1?
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What happens if the coefficients of the variable are not the same? What do you think we can do?
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Okay, so the basic idea is that we are going to multiply one or both equations by some
value, in order to make the coefficients of one of the variables the same.
Let’s try it!
Example 1:
New system:
3x + 4y = 25
x – 3y = 4
Multiply By:
Example 2:
4x + 5y = 11
6x – 7y = -27
Multiply By:
New system: