Equations With Variables on Both Sides

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Equations With Variables on Both Sides

• Ms. Turk, Algebra I
• Unit 2-4

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Check Skills Youll Need

• 6x - 2x
• 2x - 6x
• 5x - 5x
• -5x 5x
• 4x 3 -5

• 4x
• -4x
• 0
• 0
• x -2

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Example A 6x 3 8x - 21

• 6x 3 8x - 21
• - 6x - 6x
• 3 2x - 21
• 21 21
• 24 2x
• 2 2
• x 12

6x 3
8x - 21
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Example B -6d d 21

• -6d d 21
• - d - d
• -7d 21
• -7 -7
• d -3

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Example C m - 8 3m
m - 8 3m - m - m
-8 2m 2
2 -4 m
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Example D 10 - 8a 2(5 - 4a)
10 - 8a 2(5 - 4a) 10 - 8a 10 - 8a
8a 8a 10 10 Always true!
This equation is called an identity.
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Example E 2(x - 4) 2x - 8
2(x - 4) 2x - 8 2x - 8 2x - 8 -
2x - 2x -8 -8 Always true! This
equation is an identity.
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Identity
An equation that is true for every value of the
variable. The equation 3x 3x is an identity.